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Medical Mycology 253
7 Medical Mycology
Evelyn K. Koestenblatt, MS, MT (ASCP)
Jeffrey M. Weinberg, MD
C o n t e n t s
7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .255
7.2 Superficial Mycoses . . . . . . . . . . . . . . . . . . . . . . . . . .256
7.3 The Dermatophytes . . . . . . . . . . . . . . . . . . . . . . . . . .258
7.4 Subcutaneous Mycosis . . . . . . . . . . . . . . . . . . . . . . .269
7.5 Dimorphic Fungi Causing Systemic Disease . . . . 273
7.6 Opportunistic Organisms . . . . . . . . . . . . . . . . . . . . .276
7.7 Miscellaneous Organisms Causing Fungus-like Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .282
7.8 Random Facts and Summary Table. . . . . . . . . . . .283
For practice exam questions and interactive study tools, visit the Dermatology In-Review Online
Practice Exam and Study System at
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Medical Mycology 255
7.1 INTRODUCTIONYeasts: Unicellular oval to round cells, reproduce by budding or fission and form moist colonies.Moulds: Filamentous fungi, characterized by tubular branching cells called hyphae, which
form fuzzy, velvety or smooth colonies.Yeasts and moulds are not mutually exclusive: Dimorphism-mould form in the environment
(25° C), yeast or spherule form in tissue (37° C).
Microscopic Appearance• Hyphae: Vegetative tube-like structures, mass of hyphae = mycelium
– Septate: Transverse cross walls form within the hyphae– Nonseptate: Protoplasm and nuclei run along the length of the hyphael strand
uninterrupted• Pseudohyphae: Seen in yeast, resemble true hyphae except:
– Constricted at septations– Branching occurs at septations– The terminal cell is smaller than the others
• Types of Mycelium: No reproductive capability– Racket forms: Club-shaped cells– Favic chandeliers: Terminal hyphael branches having an antler-like appearance– Pectinate bodies: Hyphae resembling a comb– Spiral hyphae: Hypha forming corkscrew-like turns– Nodular bodies: A knot-like structure of hyphae
• Types of reproduction– Sexual reproduction: Fusion of compatible nuclei with meiosis– Asexual reproduction: Mitosis• Arthroconidia: Formed by fragmentation of hyphae, may appear as thick- or thin-
walled rectangular cells, example: mould form of Coccidioides immitis• Blastoconidia: Formed by budding, example: yeast• Chlamydoconidia: Thick-walled round cell, resistant to the environment, example:
Trichophyton tonsurans• Sporangia: Spores that are produced in a sac, example: Zygomycetes• Conidia: Cells produced on the end or sides of hypha or conidiophore, the size shape
and arrangement are generally characteristic of the organism, example: Dermatophytes
Direct Microscopic Examination• Potassium hydroxide (KOH): Rapid, easy, reliable diagnosis of fungal infections• SwartzLamkins:Containsacounterstain• KOHwithDMSO(dimethylsulfoxide)• ChlorazolBlackE-chitinspecific• Calcofluorwhite-mostsensitive,glucanspecificimmunofluorescentstain• Histologystains:
– Gormori Methanamine Silver (GMS)– Periodic Acid Schiff (PAS)– Fontana-Masson– Mayer’s Mucicarmine – Fite stain
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Media•Sabouraud Dextrose Agar (SDA) Emmons modification: Gold standard
– Nutritionally poor: dextrose, peptones, water, agar, encourages sporulation• SDA with cycloheximide and chloramphenicol (Mycosel or Mycobiotic)
– Good for hair skin and nails– Cycloheximide inhibits rapidly growing nonpathogenic moulds and some pathogens
(Cryptococcus neoformans, some Candida species, Prototheca, Scytalidium species, yeast forms of Histoplasma and Blastomyces)
– Chloramphenicol inhibits bacterial flora• Dermatophyte test media (DTM)
– Good for hair, skin, and nails– Contains peptones, dextrose, gentamicin, chlortetracycline, cycloheximide, phenol red– Dermatophytes utilize protein as a carbon source producing alkaline by-products causing
the media to turn from amber to red. Nondermatophytes cause the media to turn yellow due to acid by-products
7.2 SUPERFICIAL MYCOSES
Figure 7-1. Pityriasis versicolor biopsy
Pityriasis Versicolor (Tinea Versicolor)•Mostcurrentnomenclature: Malassezia furfur, M. pachydermatis, M. dermatis, M. obtuse, M. restrica, M. sympodialis, M. slooffiae• Lipophilicorganisms• Foundworldwide,preferhumid,moist,warmenvironmentand↑ CO2 tension• Appearasroundtoovalyeastformsonnormalskininsebumrichareas
• Conversiontohyphaeandspore,“spaghettiandmeatballs”• Mild,chronic,sharplydemarcatedhyper/hypopigmentedmaculeswithfinescaling• Lesionsmostoftenseenonneck,shoulders,chest,back,upperarms,abdomen• Woodslamp(+)paleyellowfluorescence• Implicatedinotherdiseases:folliculitis(Pityrosporumfolliculitis),seborrheicdermatitis,
atopic dermatitis, invasive infections, onychomycosis• KOH: Curved septate hyphae with short chains or clusters of budding thick-walled yeast
cells, may see only hyphae or only yeast cells• Culture: Organismsdifficulttogrow,requiresoliveoiloverlay• Topical treatment: Seleniumsulfide,ketoconazoleshampoo,topical“azoles,”ciclopirox• Systemic treatment: Ketoconazole,itraconazole,fluconazole
Medical Mycology 257
Tinea Nigra Palmaris (Superficial phaeohyphomycosis)• NewName:Hortaea werneckii Formerly: Phaeoannellomyces werneckii • Asymptomatic,browntoblack,macular,nonscalylesionsonpalmsofhandorsolesoffeet;
deeper pigmentation at advancing border• Warmhumidclimates:southernU.S.,SouthAfrica,Caribbean,FarEast,Europeand
Australia, Central and South America• Foundindecayingvegetation,soil,beachsand,water• KOH: Olivemultiplebranching,septatehyphaewithbuddingyeastcells• H & E: Dark organisms confined to stratum corneum, variety of shapes• Culture: Shiny black yeast colonies, composed of 2-celled yeast, later colony looses shine as
it develops thick-walled dark hyphae with oval, clear to dark 1 or 2-celled conidia• Treatment: Whitfield’sointment,azolecreams• Differential diagnosis: Junctional nevi, melanoma, Addison’s disease, hyperpigmentation of
syphilis and pinta, chemicals/dyes
Piedras• Limitedtohairshaft,characterizedbyfirm,irregularnodulescomposedoffungalelementsBlack Piedra• Piedraia hortae• Foundinsoilandwaterinhumid,tropicalareas
• Black, firm, adherent concretions 1 mm diameter, most common in scalp, also found in pubic area, beard and mustache
• KOH: Dark hyphae, ascospores containing asci held together with cement-like substance• Culture: Small, compact black-greenish velvety colony with raised center. Septate dark
thick-walled hyphae with intercalary chlamydospores• Treatment: Cut off hair, antifungal shampoo• Differential diagnosis: Nits, hair shaft defects, hair casts
White Piedra• New nomenclature: Trichosporon ovoides and T. inkin, formerly Trichosporon beigelii• Keratinophilicsoil,waterandsewageorganism,seenintemperateregions
• Tan to white soft, nonadherent small concretions ~1mm, seen on scalp, beard, mous-tache, pubic areas. Hairs may fluoresce
• KOH: Sleeve of hyphae, blastoconidia, and arthroconidia around hair. Nodules thickest at center and taper on ends
• Culture: Cream to yellow colored pasty colony and pseudohyphae with blastoconidia, arthroconidia form in older cultures, inhibited by cycloheximide
• Other superficial infections: Onychomycosis,paronychia,post-opwoundinfections• Treatment: Topical Amp B lotion, benzoic acid, salicylic acid, cut off hair, antifungal shampoo• Differential diagnosis: Lice,nits,haircasts,trichomycosisaxillaris• Trichosporanosis
– Trichosporon asahii– Disseminated disease seen mainly in immunocompromised patient with severe neutropenia–Cutaneouslesions:Erythematoustoviolaceouspapulesthatmayprogresstonecrotizing
lesions, nodular skin lesions, no concretions on hair– Treatment: Fluconazole, voriconazole, granulocyte infusions
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7.3 THE DERMATOPHYTESIntroduction
• Dermatophyte: Group of closely related filamentous fungi, which colonize keratin such as the stratum corneum of the epidermis, hair, nails, feathers of various animals
• Dermatophytosis: Cutaneous infections of keratinized tissue by the dermatophyte genera of fungi, Trichophyton, Microsporum, and Epidermophyton
• Dermatomycosis: Organismsotherthanthedermatophytesthatmaycausedeepfungalorsystemic infections with cutaneous manifestations
Ecology of Dermatophytes• Geophilic: Liveinsoil;inflammatoryinfectioninhumans• Zoophilic: Primarilyinfectsanimals;humansbecomeinfectedthroughdirectindirect
contact, infections are generally suppurative. Animals may be asymptomatic carriers• Anthropophilic: Transmitted human to human directly or indirectly through fomites.
The response can vary from minimal to markedly inflammatory with pustule or kerion production
Table7-1.EcologyofCommonDermatophytes
Geophilic Zoophilic Anthropophilic
M. gypseum M. canis E. floccosum
M. nanum M. gallinae M. audouinii
M. vanbreuseghemii M. nanum M. ferrugineum
T. equinum T. concentricum
T. mentagrophytes T. megninii
T. verrucosum T. mentagrophytes
T. rubrum
T. schoenleinii
T. soudanense
T. tonsurans
T. violaceum
Common Dermatophyte Infections
Factors Favoring Dermatophyte Infection• Largeinoculumsize• Suitable environment: Hydration, friction, maceration, heat, darkness, occlusion• Growthrateoffungusmustbegreaterthanepidermalturnover
Tinea Capitis• Dermatophyteinfectionofthescalpandhair,generallyseeninchildhood
Ectothrix• Arthroconidiacoattheoutsideofthehair,cuticledestroyed• Fluorescent(Woodslight,366nm,mercurylampwithanickelchromiumoxidefilter,
fluorescence is due to pteridine production)
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Fluorescent Endothrix Favus No Hair Involvement
• Nonfluorescent: T. mentagrophytes, T. rubrum, T. verrucosum, T. megninii, M. gypseum, M. nanum
• KOH prep: Arthroconidia are visualized on outside of hair shaft
Endothrix “Black Dot Ringworm”• Arthroconidiainvadeinteriorofthehairshaft• Blackdotsareremnantsofbrittlehairbrokenatthesurface
of the scalp, cuticle intact• T. rubrum, T. gourvilli, T. yaounde, T. tonsurans, T. soudanense, T. violaceum• KOH prep: Arthroconidia within hair shaft
Favus• Chronicinfectionofthescalp-beginsinchildhoodandmayextendintoadulthood• Scutula: Yellowish cup shaped crusts made up of hyphae and keratinous debris, may
have a single hair piercing through the center• PrimarilyT. schoenleinii, occasionally T. violaceum, M. gypseum• KOH prep: Hyphae and airspaces within hair shaft
Treatment• Griseofulvin,itraconazole,terbinafine,andseleniumsulfideorketoconazoleorloprox
shampoo
Kerion• Boggy,oozinginflammatoryreactiontofungus• Regionallymphadenopathy• Scarringalopeciamayresult• MostfrequentlyduetoM. canis, T. tonsurans,
T. verrucosum, T. mentagrophytes
Differential Diagnosis• Seborrheicdermatitis,impetigo,folliculitis,lupus,psoriasis,alopeciaareata
Table 7-2. Tinea Capitis
Fluorescent Non-Fluorescent
M. audouinii M. gypseum* T. gourvilli T. schoenleinii* E. floccosum
M. canis M. nanum T. rubrum T. violaceum T. concentricum
M. distortum T. megninii T. tonsurans M. gypseum*
M. ferrugineum T. mentagrophytes T. soudanense
T. rubrum T. yaounde
T. verrucosum T. violaceum
* May fluoresce
uTIPa�Pruritis, fever, pain, regional
lymphadenopathy, scarring alopecia
aTreatment may include prednisone
MNEMONICFluorescent Ectothrix Fungi
Cats And Dogs Fight and Growl
Sometimes
M. canis
M. audouinii
M. distortum
M. ferrugineum
and sometimes
M. gypseum
T. schoenleinii
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Tinea Corporis• Anyofthedermatophytesarecapableofcausingtineacorporis;themostfrequently
recovered organisms include: T. rubrum, T. mentagrophytes, M. canis, T. tonsurans• Transmitteddirectlyfromindividuals,animalsorfomites• Organismsinvadestratumcorneumgenerallycausinganannularlesionwithan
erythematous raised, scaly advancing border, the center of the lesion may show clearing
Tinea Imbricata• T. concentricum; endemictoSouthPacific,S.&C.AmericaandFarEast.Polycyclicscaly
noninflammatory lesions
Tinea Profunda• Verrucose inflammatory response, patients may have defective cellular immunity
Majocchi’s Granuloma• Granulomatous lesion of hair follicle, generally associated with T. rubrum, requiresbiopsy
for dx and oral antifungal
Differential Diagnosis• Seborrheic,atopicorcontactdermatitis,psoriasis,impetigo,lichensimplex,nummular
eczema, tertiary syphilis
Tinea Barbae• Inmen,thebeardedareaofthefaceandneck,generallyinflammatory• Associatedwithexposuretoanimals• Inflammatory: T. mentagrophytes, T. verrucosum• Superficial form: T. violaceum, T. rubrum• Abscess: M. canis• Verrucous granulomatosis: E. floccosum• Requiresoralantifungal
Tinea Cruris• Mainlyseeninmales,involvesthegroin,perinealandperianalskin• Directorindirectcontact• E. floccosum, T. rubrum, T. mentagrophytes
Tinea Faciei• Femalesandchildrenmostfrequentlytheupperlipandchin• Maybehistoryofanimalexposure• T. rubrum, T. mentagrophytes, T. concentricum, M. canis
Tinea Manuum• Palmar/interdigitalareasofthehands,almostalwaysassociatedwithT. pedis• T. rubrum, T. mentagrophytes, E. floccosum
Tinea Pedis• Moccasin type: E. floccosum, T. rubrum• Interdigital type: E. floccosum, T. mentagrophytes• Vesicular type: T. mentagrophytes• Interwebinfectionsofteninvolvefungi,yeast,gramnegativeandpositivebacteria
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Tinea Unguium• Dermatophyteinfectionofthenails
Onychomycosis• Fungalinfectionofthenailsduetodermatophyte,yeast
or nondermatophyte
Distal Lateral Subungual Onychomycosis• Infectionbeginsdistallyandinvolvesthenailbed,nailplateandlateralnailfold;thicknailwithdebris,looseorcracked nail plate
•T. rubrum
Proximal White Subungual Onychomycosis•Rarestformofonychomycosis•AIDSmarker•Organismsenterthecuticleandinfecttheproximalpartofthenailbedcausingwhite
islands that slowly invade the nail plate•T. rubrum mostfrequentlyrecovered•AlsoT. megninii, T. schoenleinii, T. tonsurans, T. mentagrophytes, E. floccosum
White Superficial Onychomycosis•Organisminvadesthesurfaceofthenailplateoftoenailsonly•Irregularwhitechalkyopaquepatchesonthenail• MostfrequentT. mentagrophytes, also Aspergillus species esp. terreus, Acremonium
(formerly Cephalosporium), Fusarium, Scopulariopsis• InHIVpopulation,generallycausedbyT. rubrum
Tinea Incognito• Theuseofcorticosteroidscancauseanatypicalappearinglesion
Dermatophytids• Eczematousallergicreactiontodermatophyteinfectionelsewhereontheskin• Lesionsaresterile;reactionclearsafterfungushasbeeneradicated• Patientwilltestpositivetogroup-specifictrichophytonantigen
Table 7-3. Genus Differentiation
Epidermophyton Trichophyton Microsporum
Microconidia not produced Microconidia diagnostic, numer-ous with characteristic arrange-ments and shapes (some species do not produce conidia)
Microconidia not distinctive
Macroconidia smooth-walled, club-shaped, 2–6 cells, occurs singly or in clusters, thin and thick cell walls
Macroconidia not distinctive, smooth, thin cell wall, pencil-shaped
Macroconidia diagnostic, rough-walled (echinulate), multicellular, barrel-shaped, thick cell wall
No hair involvement Nonfluorescent ecto- and endo-thrix invasion
Fluorescent & nonfluorescent ectothrix invasion
uTIPaDistal Lateral Subungual Onychomycosis • T. rubrumaProximal White Subungual Onychomycosis • AIDSmarker • T. rubumaWhite Superficial Onychomycosis
• T. mentagrophytes
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Epidermophyton
Figure 7-2. E. floccosum
E. floccosum• Anthropophilic: Worldwide• Nohairparasitism,Tinea cruris, T. pedis, occasionally T. corporis, onychomycosis• Colony morphology: Khaki-coloredcolony,orange-brownreverse,radialgrooves,folded
center, velvety• Microscopic morphology: Septate hyphae, no microconidia, macroconidia smooth, thin-
and thick-walled, club-shaped, two to six cells, occur singly or in characteristic clusters (no other species does this)
Microsporum Species
Figure 7-3. M. audouinii
M. audouinii• Anthropophilicorganism:Worldwide• Tineacorporis,formerlythe#1causeofT. capitis in children (fluorescent ectothrix)• Colony morphology: Grey to tan colony, reverse salmon with a reddish brown center, flat surface,“mousefurappearance”
• Microscopic morphology: Septate hyphae with terminal chlamydoconidia often with pointedends.Pectinatebodies,racquethyphaeandfavicchandeliersmayoccur.Rarelysee macroconidia, when present poorly shaped, thick-walled and echinulate. Microconidia occasionally seen
• Miscellaneous: Polished Rice (–)
Medical Mycology 263
Figure 7-4. M. canis
M. canis• Zoophilicorganism(catsanddogs)
• Most common cause of T. capitisworldwide (fluorescent ectothrix)• T. corporis, T. faciei, T. unguium, T. pedis (rarely)• Colony morphology: Whitefluffy,fur-likecolonywithyellowperipheryandfeathery
border. Reverse deep yellow• Microscopic morphology: Septate hyphae. Macroconidia are numerous, spindle shaped, thick-walledwithknoblikeends(“dog’stail”)havingsixormorecells.Occasionalclub-shaped microconidia
• Miscellaneous: Polished Rice (+)
M. canis var. distortum• Zoophilicorganism:FoundinAustraliaandNewZealand• Fluorescentectothrixtineacapitis• Colony morphology: Whitetobuffvelvety,fluffycolony.Reverseyellow• Microscopic morphology: Septate hyphae. Macroconidia resemble distorted M. canis,
microconidia present• Miscellaneous:PolishedRice(+)
M. ferrugineum• Anthropophilicorganism:FoundAsia,IndiaandAfrica• Fluorescentectothrixtineacapitis,similartoM. audouinii, Tinea corporis• Colony morphology: Smooth, waxy, heaped, rust colored colony. Reverse cream to yellow
orange• Microscopic morphology: Longstraightseptatehyphaewithprominentcrosswalls,bamboo-like.Occasionalchlamydoconidia.Noconidia
M. gallinae• Zoophilic organism: Chicken favus• Rarelycausesectothrixtineacapitis• Colony morphology: Fluffy to felt-like white colony becoming pink with age. Reverse
strawberry red diffusible pigment• Microscopic morphology: Septate hyphae. Macroconidia-large echinulate at tip, club-
shaped, may be curved, four to ten cells, microconidia present
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Figure 7-5. M. gypseum
M. gypseum Complex• Geophilicorganismhumaninfectionresultsfromdirectcontactfromthesoil• T. corporis, ectothrix tinea capitis, often inflammatory, may see favus-like crust, and
occasionally a dull fluorescence• Colony morphology: Flat, powdery colony, buff to cinnamon with a white periphery.
Reverse yellow to orange or purplish in spots• Microscopic morphology: Septate hyphae. Macroconidia numerous, symmetric, up to six
cells, microconidia club-shaped• Miscellaneous: Polished Rice (+)
Figure 7-6. M. nanum
M. nanum • Zoophilic/geophilicorganism• Pigringworm,ectothrixtineacapitis• Colony morphology: Fluffy white colony → powdery beige. Reverse orange to reddish brown• Microscopic morphology: Septatehyphae.Macroconidiaechinulate,eggshapedor“pigsnout”withatruncatedbase,onetothreecells,microconidiaclub-shaped
M. vanbreuseghemii• Geophilicorganism• Rarelyinfectshumansandanimals• Colony morphology: Fluffy to powdery colony, cream, tan to pink in color. Reverse
colorless to yellow• Microscopic morphology: Septate hyphae, macroconidia long, tapered, echinulate, thick-
walled with seven or more cells, microconidia present
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Trichophyton Species Biochemical Testing 1.) In vitro hair perforation
(+)wedgeshapedareasinhairshaft→ T. mentagrophytes(–) no change in hair shaft → T. rubrum
2.) Pigmentation production on cornmeal agar with 1% dextrose(+)T. rubrum, (–) T. mentagrophytes
3.) Trichophyton agars tests—for growth factor requirementsThiamine T. verrucosum
T. concentricum T. violaceum T. tonsurans Niacin T. equinum Histidine T. megninii Inositol and thiamine T. verrucosum 4.) Urease test(+)red-pink T. mentagrophytes (–) amber T. rubrum
T. equinum• Zoophilicorganism• Frequentcauseofinfectioninhorses,rarelyinfectshumans• Colony morphology:Creamtoyellowfluffycolonywithradialgrooves;reversebright
yellow to dark pink or brown• Microscopic morphology: Septate hyphae. Macroconidia rarely seen, fusiform,
microconidia tear drop shaped laterally along hyphae• Miscellaneous: Requiresniacin(“Horsesarenice”)
T. megninii• Anthropophilic organism: SeeninAfricaandEurope• Primarily causes: T. barbae; ectothrix T. capitis, T. corporis, T. unguium• Colony morphology: Whitetopinksuedelikecolonyflatorwithgentlyfolds;reversered• Microscopic morphology: Septatehyphae.Macroconidiapencil-shaped;microconidiatear
drop, resembles T. rubrum• Miscellaneous: Requireshistidine
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Figure 7-7. T. mentagrophytes
T. mentagrophytes• Multiplevarieties
– Anthropophilic: T. mentagrophytes var. interdigitale (fluffy colony)– Zoophilic: T. mentagrophytes var. mentagrophytes (powdery colony)
• BullousT. pedis, T. corporis, T. barbae, white superficial onychomycosis, ectothrix T. capitis• Colony morphology
– Anthropophilic: Fluffy white colony some powdery areas– Zoophilic: Powdery buff colony– Reverse rose brown to red
• Microscopic morphology: Septatehyphae,spiralhyphae;macroconidianotalwayspresent,cigar-shaped, thin-walled microconidia– Anthropophilic: Fluffy form – few, smaller teardrop shaped, can be confused with T. rubrum– Zoophilic: Powdery form – abundant, round clusters on branched conidiophores– Miscellaneous:Hairperforation(+),pigmentationproductionCMagar1%dex(–),urease(+)
Figure 7-8. T. rubrum
T. rubrum• Anthropophilic organism: Most common dermatophyte worldwide• T. pedis, T. manuum, T. corporis, T. cruris,onychomycosis, Majocchi’s granuloma, rare
cause of T. capitis• Colony morphology: Fluffy to granular white to cream colony with a central elevation, someradialfolding;reversenondiffusiblered,occasionallyyellow-orange
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• Microscopic morphology: Septatehyphae.Macroconidiarare,thin-walled,pencil-shaped;microconidiadelicateteardropshapedappearlaterallyonhyphae:“birdsonawire”;arthroconidia form from hyphae and macroconidia
• Miscellaneous: Hairperforation(–),pigmentationproductionCMagar1%dex(+),urease(–)
T. soudanense• Anthropophilic organism:CentralandWestAfrica• EndothrixTineacapitis similar to T. tonsurans, T. corporis• Colony morphology: Flattofoldedsuede-likeapricotcoloredcolonywithafringedborder;
reverse deep yellow• Microscopic morphology: Septate hyphae with reflexive branching, arthroconidia, chlamydoconidia;Microconidiateardropshaped,macroconidianotseen
• Miscellaneous: Urease (–)
Figure 7-9. T. tonsurans
T. tonsurans • Anthropophilicorganism
• Most common cause ofT. capitisin the U.S. (black dot nonfluorescent endothrix)• Tineacorporis,rarelyT. unguium, T. pedis• Colony morphology: Highlyvariable;powderytosuede-like,oftenwithradialfolds.Colorvariesyellow,brown,white,gray,orrose;reversereddishbrown,whichmaydiffuseintoagar
• Microscopic morphology: Septatehyphaewithspiralcoils,chlamydoconidia,arthroconidia;macroconidia rare, irregular, smooth-walled. Microconidia numerous, variable, shape and size;teardrop,balloonforms,matchstickforms
• Miscellaneous:Partialrequirementforthiamine
T. concentricum• Anthropophilic organism: South Pacific Islands, Asia, South America, Mexico• Tineaimbricata(Tokelau),notknowntoinvadehair• Colony morphology: White,waxycolonyturnsamberorcoralredanddeeplyfolded,
cerebriform• Microscopic morphology: Tangled septate hyphae without micro or macroconidia• Miscellaneous: Some strains are enhanced with thiamine
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Figure 7-10. T. schoenleinii
T. schoenleinii • Anthropophilic:MiddleEast,Europe,Africa,rareinU.S.• Tineacapitis:favus,dullfluorescence,diffuse,scarringalopecia,hairsremainlong,scutula• T. corporis, T. unguium • Colony morphology: Heapedupsuedecolonyusuallygrowsdeepintoagar,cerebriform;
reverse colorless to yellow• Microscopic morphology: Septate hyphae with favic chandeliers and chlamydoconidia, few
if any conidia
T. verrucosum • Zoophilic organism: tinea of horses, cattle and dogs• EctothrixT. capitis, inflammatory T. barbae, T. corporis, T. faciei• Colony morphology: Smallfoldedandheaped,waxy,whitecolony;reversecolorlessto
yellow• Microscopic morphology: Best growth at 37˚C: thick irregular branching hyphae with
chains of chlamydoconidia• Growth at 37˚ C with thiamine: Microconidia, occasional macroconidia shaped like string
beans• Miscellaneous:Growsbestat37˚C,requiresthiamine,somestrainsalsorequireinositol
T. violaceum• Anthropophilic organism: SouthernEurope,Asia,Africa,MiddleEast,C.&S.America,India• T. capitis, endothrix, black dot, similar to T. tonsurans• Maycausefavus• T. corporis, T. barbae, occasionally T. unguium• Colony morphology: Waxy,cerebriform,heapedpurplecolony;reversedeepportwine• Microscopic morphology: Septate tangled, irregular hyphae with intercalary
chlamydospores. Few macro and microconidia form with thiamine enrichment• Miscellaneous: Partialrequirementforthiamine
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Dermatophyte-like Infections (Dermatomycosis)
Figure 7-11. Scytalidium dimidiatum
Scytalidium dimidiatum• Dematiaceous(pigmented)organismcausingdermatomycosesofthesolesandtoe
webs, paronychia, and onychomycosis• SeeninsoutheasternU.S.,S.America,Caribbean,Africa,India,FarEast• Recoveredfromsoil,plantpathogen• KOH: May look similar to dermatophytes, or be contorted with wide and narrow hyphae,
don’t always see pigmentation of hyphae• Colony morphology: Initiallywoollywhitecolonyturninggraytoolivebrown;reverse
gray to black• Microscopic morphology: Hyaline to olive brown pigmented, septate hyphae of variable
widths. Forms thin- to thick-walled, round to rectangular, one to two celled arthroconidia• Miscellaneous: Sensitive to cycloheximide, resistant to most antifungals
7.4 SUBCUTANEOUS MYCOSIS
Figure 7-12. Sporothrix schenckii (culture) Figure 7-13. Sporotrichosis (biopsy)
Sporotrichosis • Sporothrix schenckii• Foundworldwide,highestrateisinMexico,Brazil,andSouthAfrica• Risk factors: Gardener, farmer, florist, mason, miners, animal handlers (dog, cat, insects,
parrot, horse, rat, armadillos), alcoholism
270 2011/2012 Dermatology In-Review l Committed to Your Future
• Sources: Organismsliveinsoil,organicmaterialex.roses,thorns,sphagnummoss,minetimbers, tree bark, straw, grasses
• Transmittedbydirectinoculationandinhalation• Lymphocutaneous-subcutaneous nodules, ulceration, lymphatic spread• Fixed cutaneous: Lesionwithoutlymphaticspread,duetopriorexposure• Disseminated: Mucocutaneous, pulmonary, osteoarticular,
genitourinary, meningitis• KOH: Oftennothelpful,organismsdifficulttodemonstrate
•Biopsy:StainspoorlywithH&E,betterseenwith PAS,GMS,“cigarbodies”orroundyeastcells4-6m
• AsteroidBody:Yeastcellsurroundedbyeosinophilicfringe
• Directimmunofluorescences,serology,andsporotrichinskintest• 25°C:Cream-coloredcolonylaterbecomesbrowntoblack,leatheryorvelvety&fold;
septate delicate hyphae with conidiophores developing at right angles from the hyphae with conidia developing at the tip in a flowerette arrangement
• 37° C:Yeast-likecolony;maybegrayorcreamcolored,cigarbodies(1-3µm x 3-10 µm) and round yeast cells (10 µm), multiple budding yeast cells seen
• Lymphocutaneous:Itraconazole,SSKI,terbinafine, fluconazole, heat therapy• Disseminated: Itraconazole and/or amphotericin B
Mycetoma (Maduromycosis, Madura Foot, Fungus Tumor)• HighestincidencealongtheTropicofCancer—Sudan,
Mexico, India, Central and South America, Africa• Organismsaresoilorplantsaprophytes• Penetratingwoundmostcommonlyfoot(70%),lowerleg
hands, upper back, neck, shoulders
•CollectgrainsforKOH,histologyandculture• Biopsy: Histiologic features of actinomycotic and
eumycotic are similar. Grain located in the abscess or sinus tract surrounded by neutrophils, multinucleated giant cells, necrotic debris, and pallisading epitheloid cells
Eumycotic •Containhyphae(2-6µm wide) and chlamydoconidia •Doesnotstainwithgramstain,butstainswellwithGMS,PAS •Treatment: Debridement, itraconazole, ketoconazole, voriconazole, posaconazole •Relapsescommon
uTIPa Differential diagnosis: cutaneous
leishmaniasis, cat scratch disease,
mycetoma due to Nocardia,
S. apiospermum, TB, M. kansasii, M. marinum, deep fungal infection
uTIPa�Caused by true fungi (eumycotic) or
filamentous bacteria (actinomycotic)
a�Disease progresses slowly; triad of
tumefaction, draining sinuses, grains or
granules (aggregates of organism)
causing scarring, swelling, deformity,
bone involvement may occur
Medical Mycology 271
Table7-4.EumycoticMycetoma
Etiologic Agent Color of Grain
Acremonium spp. white
Aspergillus spp. white
Curvularia spp. black
Exophiala jeanselmei black
Fusarium spp. white
Leptoshaeria spp. black
Madurella grisea black
M. mycetomatis black – most common in Africa
Pseudalleschella boydii, Scedosporium apiospermum(asexual state)
white-yellow – most common in N. America
Pyrenochaeta romeroi black
Figure 7-14. Actinomycotic Granule
Actinomycotic• Finebranchingfilaments0.5–1.5mmtendtobreakupintoshortbacillaryandcoccoidforms• Staingram(+);stainswellwithGiemsa,Brown-Brennen;maynotstainwellwithH&EorPAS• Nocardia sp.aregram(+),partiallyacidfast(fitestain)duetolongchainfattyacidsincellwall;NocardiosiscausedbyN. asteroides and N. brasiliensis and can manifest as pustules, cellulitis, ulcerations, abscesses and draining sinuses
• Treatment of choice: Trimethoprim/sulfamethoxazole, netilmicin, amikacin, erthryomycin, 3rd generation cephalosporins, minocycline
272 2011/2012 Dermatology In-Review l Committed to Your Future
Table 7-5. Actinomycotic Mycetoma
Etiologic Agent Color of Grain
Actinomadura madurae yellow – white
Actinomadura pelletieri red – most common in Africa
Nocardia asteroides white – common in Central America
Nocardia brasiliensis white – Mexico (most common)
N. otitidiscaviarum white
Nocardiopsis dassonvillei cream
Streptomyces somaliensis yellow – white to brown
Figure 7-15. Chromoblastomycosis (biopsy)
Chromoblastomycosis (Chromomycosis, Verrucous dermatitis) • Seenmainlyintropicsandsubtropics,especiallyC.&S.
America, Africa, Cuba, Puerto Rico, Caribbean Islands, Australia, Japan
• Saprophyticorganismsfoundinsoil,decayingvegetation, wood
• Traumaticinjuryinagriculturalworkerstofoot,leg,occasionally chest, shoulders
• Cauliflower-liketumorsmaycoalesce,irregularverrucoseplaques,nodules,annularwithacentralclearing, transepidermal elimination
• Complications: Include 2° infection, lymphedema, elephantiasis, SCC
• Mayseedematiaceoushyphaeinearlylesions• KOH: Brown, round thick walled septate cells• Culture: Allorganismsappearsimilar—black,velvetytoslightlypowderycolonies• Treatment: Surgery,itraconazole,+/–flucytosine,terbinafine,amphotericinB
Lacaziosis (KeloidalBlastomycosis,Lobomycosis,Lobo’sDisease)• Lacazia loboi formerly Loboa loboi• Brazil,Caribbean,associatedwithbottle-noseddolphins
uTIPa Fonsecaea pedrosoi (most common),
Fonsecaea compacta, Rhinocladeilla
aquaspersa, Phialophora verrucosa,
Exophiala jeanselmei, Cladophialophora
carrionii
uTIPa�Biopsy: pseudoepitheliomatous hyperplasia,
epidermal microabscess, granulomatous
tissue response, “copper pennies” (sclerotic
bodies, medlar bodies, chromobodies)
a� Copper pennies → brown, round, thick walled
cells 5-12 µm with septations
Medical Mycology 273
• Painlesskeloids,nodules,occasionallyulcers,verrucoselesionsonfaceandupperextremities
• Noinflammatoryreactionaroundskin• Biopsy: Single or multiple budding thick walled cells 9-10 µm, appear to be attached by a
bridge, found free or phagocitized in a granulomatous reaction →“chainofcoins”or“brassknuckles,”stainswithFontanaMassonstain
• Organismnotculturable• Treatment: Surgical excision (antifungals ineffective)
7.5 DIMORPHIC FUNGI CAUSING SYSTEMIC DISEASE Introduction
• Virtuallyallorgansaresusceptible• Endemicprimarypulmonaryinfections• Oftenself-limiteddisease• Seeninimmunocompetentandimmunocompromisedpatients• Immunityfollowingdisease• Canproducecutaneousmanifestationswithorwithoutsystemicinvolvement• Seeincreasedmortality:don’thaveagoodwaytoIDthesediseasesinatimelyfashion• Antibodytestingisavailableformostoftheendemicmycoses
Figure 7-16. Histoplasma capsulatum (mold form)
Histoplasmosis (Cave Disease, Darling’s Disease) • Histoplasma capsulatum var. capsulatum• Soilenrichedwithbat,bird(especiallystarling),andchickendroppings• Runsthespectrumfromasymptomatictoprogressive
dissemination with hematogenous spread to multiple organs
• Toxicerythema,erythemamultiforme,erythemanodosum• Disseminationtobone,GItract,spleen,liver,lymphnodes,
arthritis seen in AIDS patients• CutaneousmanifestationsinAIDS:nonspecificlesions—macules,papules,nodules,ulcers
(oral and rectal), impetigo, cellulitis, molluscum-like• Primary cutaneous: Very rare, lab accident, direct inoculation: chancre with
lymphadenopathy
uTIPaPrimary pulmonary infection
a�Endemic to Ohio, Mississippi, Missouri
River Valleys, Caribbean Islands,
Syracuse NY
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• Biopsy: Intracellular organisms may be budding or singular, 2-4 µm, budding cells have a narrowisthmusofattachment;donothaveacapsule(shrinkageartifact);lookforahaloaround the organism
• Differential diagnosis:Leishmania,toxoplasmosis,penicilliosis,cryptococcosis,blastomycosis• 25˚C: Whitecottonycolony, turns tan with age, septate hyphae with pear shaped
microconidia 2-5 µm and round thick walled tuberculate macroconidia 7-15 µm (Figure 7-16)• 37˚C: Moist yeast colony, small round to oval budding cells 2-5 µm, inhibited by
cycloheximide• Treatmentwillvarydependingonclinicalmanifestationofdisease.Fordisseminated
disease: Amphotericin B followed by itraconazole, fluconazole, posaconazole, voriconazole, or ketoconazole
African Histoplasmosis• Histoplasma capsulatum var. dubosii, endemic to Africa• Affectsskinandbone;drainingpapules,abscesses,ulcers• Yeastphase10-15µm with a thick wall, cluster in giant cells
Figure 7-17. Blastomyces (biopsy)
Blastomycosis (North American Blastomycosis, Gilchrist’s Disease) • Blastomyces dermatitidis• Asymptomaticorself-limiteddiseasemanifestingasa
virus-like respiratory disease, cough, chest pain, low-grade fever
• Chronic pulmonary: Progressive, involves various organs, mimics pneumonia, Histoplasmosis, or TB
• Gilchrist’s disease: Primarycutaneousblastomycosis;usuallyanoccupationalhazard→ lab workers, dog handlers (from a dog bite)
• Disseminationtoskin(80%),bone(25–50%),genitourinarysystem,CNS• Lesionsfoundmostoften: face, mucous membranes, unclothedskinsurfaces;firstappearasnodulesorpapules
• Differential diagnosis: Coccidioidomycosis, Cryptococcosis
• 25˚C: Whitetotanfluffycolony,smallroundconidiaonconidiophores, resemble lollipops
uTIPa Southeastern U.S.: Ohio and
Mississippi River Valley, Great Lakes
area, Chicago, St. Lawrence Seaway,
Africa, Middle East, India
uTIPa�Verrucous lesions: sharp borders,
may have a central clearing → indis-
tiguishable from tuberculosis of skin
a Ulcerative lesions: usually seen in
mucocutaneous areas
uTIPa Treatment: Itraconazole drug of
choice for disseminated disease
Medical Mycology 275
• 37˚C: Cream, wrinkled, waxy colony, inhibited by cycloheximide, yeast cells-broad based, thick walls may appeardoublecontoured,“figure8”inappearance(Figure7-17)
• Treatment: Itraconazole drug of choice for non-CNS involvement, ketoconazole, voriconazole
• STD treatment for meningeal disease - Amphotericin B
Figure 7-18. Coccidioidomycosis (biopsy)
Coccidioidomycosis (CaliforniaDisease,SanJoaquinValleyFever)• Coccidioides immitis
• Endemicarea:Southern California, Arizona, New Mexico, Southwest Texas, Northern Mexico, Guatemala, Honduras, N. Argentina, Paraguay
• Organismsbecomeairborneduringarcheologicaldigs,duststorms,andconstruction• Asymptomaticandself-limitedrespiratorytractinfectioniscommon• Pulmonary:Flu-likesymptoms;erythemanodosum,erythemamultiforme,toxicerythema• Cutaneous:Veryrare;usuallyinlabworker→ chancre-like lesion, lymphadenitis• Disseminated cocci:Occurs<1%cases;disseminationtosubcutaneoustissue,bone,joints,
meninges• Lesionsappearonface,scalp,andneckaspapules,pustules,nodules,verrucous,ulcerative,
abscesses
• Biopsy: SpherulesstainwellwithPAS,GMS,H&E,10-80µm containing endospores 2-5 µm (Figure 7-18)
• Differential diagnosis: TB, cryptococcosis, deep fungals• 25˚C or 37˚C:Samemorphology—fluffywhiteortancolony.Septatehyphaewith90°
branching and many thick-walled barrel shaped rectangular arthrocondia alternating with empty cells
• Treatment for meningitis: Fluconazole or amphotericin B• Nonmeningitis: Itraconazole or ketoconazole, voriconazole
Paracoccioidomycosis (Brazilian Blastomycosis, South American Blastomycosis)• Paracoccidioides brasiliensis• Endemic area:Brazil(80%ofreportedcases),SouthandCentralAmerica• Primarilyinmaleagriculturalworkers• DisseminationtoGI,CNS,kidneys,liver,skin,lymphnodes,adrenals• Mucocutaneous lesions: Papules, vesicles, crusty granulomatous lesions• Massivelymphadenopathy
uTIPa Biopsy: granulomatous reaction,
single or broad based budding cells,
8-15 µm; diagnostic; look for thick
walls
276 2011/2012 Dermatology In-Review l Committed to Your Future
• Biopsy:“Mariner’sWheel”-large,thick-walledroundcell(5-50µm) with single and mul- tiple buddings (2-10 µm) attached to the mother cell by narrow connections
• Differential diagnosis: TB, leishmaniasis, SCC, BCC, deep fungals, especially Blastomyces dermatitidis
• 25˚C: White-brownishfoldedcompactcolony,septatehyphaewithchlamydoconidia• 37˚C:Waxycreamyeastcolony,sensitivetocycloheximide,largethickwalledcell5-50um
with single and multiple buds• Treatment of choice: Itraconazole, also amphotericin B, ketoconazole, or fluconazole
Penicilliosis• Penicillium marneffei• EndemicinSoutheastAsia,especiallyThailand,China,Vietnam• Carriedbyhealthybamboorats• Infectsimmunocompetentandimmunocompromised,especiallyAIDSpatients• Disseminatedpulmonaryinfection
• Cutaneous lesions: Molluscum-like, mucocutaneous lesions → papular and ulcerative• Fungemia• Biopsy: Intracellular and extracellular oval to round yeast shaped forms 2-4 µm with cross walls,somesausage-shaped,stainswellwithPAS,GMS,notH&E
• Differential diagnosis: Histoplasmosis, cryptococcosis• 25˚C: Downy colony, white with yellowish green areas, reverse red diffusible pigment,
phialides bearing oval conidia in chains• 37˚C:Whiteyeastcolony-roundorovalyeastlikecells3-8µm, central wall forms as the
cells multiply by fission• Treatment: Amphotericin B and/or itraconazole, voriconazole
7.6 OPPORTUNISTIC ORGANISMS Introduction
• Predisposingfactors:neutropenia,immunocompromised• Noparticularage,sex,race,orendemicarea• Organismsareofminimalvirulence• Diseaseisnotcontagious• Noimmunityfollowsinfection• Anyfunguscancauseinvasivediseaseintheimmunocompromisedhost
Aspergillosis• Aspergillussp.are2ndonlytoCandidaasthecauseofopportunisticinfectionsinpatients
who are immunocompromised• Organismsareubiquitousinnature→ leaves, grain, soil, decaying vegetation, soft contact
lens, refrigerator, walls, dust, air ducts of operation rooms• Predisposing factors for invasive Aspergillosis: Profound neutropenia, bone marrow
transplants, tissue injury, burns, long-term steroid use, broad-spectrum antibiotics, chemotherapy, elderly
• Notgenerallyseeninpatientswithcell-mediatedimmunedysfunctionexceptlatestageAIDS• Toxicity due to ingestion of contaminated food: Aflatoxins• Pulmonary: Allergy, asthma, aspergilloma (fungus ball-colonization in lungs, sinuses)
Medical Mycology 277
• Primary cutaneous: Generally due to trauma (IV and catheter sites) begin as erythematous macules,papulesorplaques→ hemorrhagic bullous and ulcerations with central necrotic eschar, may resemble cellulitis - Generally due to A. fumigatus and A. flavus
• Otitisexterna• Onychomycosis• Dissemination from primary pulmonary source to: CNS, kidney, heart, bone, GI, skin
• Necrosis,inflammation,thrombosis,bloodvesselinvasion• Bx: Beststains—GMS,PAS:dichotomouslybranchinghyphae(3µm wide) usually at 45o
angles, maybe radiating out from a focal point, see conidia with conidiophores (fruiting heads) if fungus is growing in cavity with an air space. Splendore-Hoeppli phenomenon
• Organismsevokeapyogenicreactionaccompaniedbynecrosisduetopotentendotoxins• Treatment: Amphotericin B, itraconazole, voriconazole, caspofungin, flucytosine-second line
therapy
A. flavus• Velvetyyellowtogreenorbrown• Septatehyphae,roughconidiophore.Vesiclecompletelycoveredwithphialidesand
chains of conidia
Figure 7-19. Asperillus fumigatus
A. fumigatus • Mostcommonspecies• Velvetyorpowdery,darkgreentogray• Septatehyphae,phialidesonupper2/3ofvesiclewith
chains of conidia
A. niger• Woolly,whiteturnsblackwithage• Septatehyphae,phialidescoverentirevesiclewithchains
of conidia
Zygomycosis (Mucormycosis, Phycomycosis)• Mostcommonly:Absidia, Rhizopus, Mucor• Others:Cunninghamella, Saksenaeceae,
Syncephalstrum, Conidiobolus, Rhizomucor, Basidiobolus
• Worldwide distribution: Soil, animal excreta, seeds, fruits, moldy bread, decaying vegetation
uTIPa Acute invasive zygomycosis is
characterized by: • �Aggressive�invasion�of�large�blood�
vessels�and�nerves
� • Necrosis�of�adjacent�tissue
� • Ischemia,�infarction�of�adjacent�
� �����tissue�resulting�in�black�pus
� • �Risk�factors:�neutropenia,�diabetes�
mellitus,�metabolic�acidosis,�trauma,�
organ�transplants,�systemic�cortico-
steroids,�severe�burns,�malnutrition,�
hematologic�malignancy
a Rhinocerebral zygomycosis: associated�with�acidotic�diabetes;�acute,�rapidly�
progressive�and�fatal;�infection�begins�
in�paranasal�sinus;�dark�nasal�discharge,�
facial�swelling,�� ulceration�-�most�com-
mon�form�of�disease
278 2011/2012 Dermatology In-Review l Committed to Your Future
• Rhinocerebral Zygomycosis:Associatedwithacidoticdiabetes;acute,rapidlyprogressiveandfatal;infectionbeginsinparanasalsinus;darknasaldischarge,facialswelling,ulceration - most common
• Pulmonary: Fungoma• Gastrointestinal: Malnourished• Cutaneous: Primary local trauma (contaminated adhesive tape) or disseminated, induration
and erythema, necrotic ulcer• Disseminated: Profoundly neutropenic. Starts in lungs hematogenous spread to CNS• Biopsy: BestdemonstratedwithPAS,GMS,maynotstainaswellwithH&E• Wide,ribbon-likehyphaewithirregularrightanglebranchingandveryinfrequent
septations, hyphae may be twisted and distorted. Ring-shaped structures represent x-sections of hyphae. No spores are seen
• Treatment: Amphotericin B, debridement• Organismsgrowrapidlywithgreycottoncandy-likecolonies
Figure 7-20. Zygomycosis (biopsy)
Figure 7-21. Rhizopus
Rhizopus• Mostcommon.Longunbranchedsporangiophores,roundsporangia,rhizoidsdirectly under
sporangiophores (Figure 7-21)
Mucor• Longbranchedsporangiophores,roundsporangia,norhizoids
Medical Mycology 279
Absidia• Branchedsporangiophores,conicalswellingjustbeneathsporangium,pear-shaped
sporangia, rhizoids are between sporangiophores
Hyalohyphomycosis• Disseminatedinfectionbythoseorganismshavinghyaline(nonpigmented)hyphae
Figure 7-22. Fusarium
Fusarium (Fusariosis)• MorefrequentlyseeninairsamplesthanAspergillus
• Predisposingfactors:Especiallyinpatientswithhematologicmalignancies,neutropenia,trauma, burns → most common fungus in burn patients (Aspergillus is the second most common), pneumonia, mycotic keratitis, white superficial onychomycosis, disseminated disease
• Cutaneous lesions: Target lesions, painful necrotic erythematous nodules, abscess, cellulitis• Bx: LookssimilartoAspergillus• Fluffypink,violet,yellow,greencolony• Septatehyphaewithphialideswhichproduceoval-shapedmicroconidiaandbanana
shaped macroconidia. Chlamydoconidia present (Figure 7-22)• Mortalityofpatientswithprofound,prolongedneutropenia~100%• Treatment: AmphotericinB+5FC,liposomalAmphotericinB,granulocyteinfusionmaybegivenwiththerapy,itraconazoleonly~50%effective,fluconazolealsoshowssomeresistance, voriconazole
Penicillium• Ubiquitousinnature,frequentlaboratorycontaminant• Cutaneous,externalear,mycotickeratitis,bronchopulmonary,dissemination• Blue-greencolonywithwhiteborder• Septatehyphaewithbrush-likeconidiophoresandphialideswithchainsofroundconidia
Scopulariopis• Whitesuperficialonychomycosis• Powdery,browncolony• Septatehyphaewithbrushlikephialidesproducingchainsofround,thick-walledrough
conidia
Paecilomyces• Immunocompromisedpatients• Erythematousmacules,vesicles,pustules,nodules
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• Pinkish,oryellowish-browncolony• Septatehyphaewithtaperedphialidesandelliptical-shapedconidiainchains
Figure 7-23. Phaeohyphomycosis Fontana-Masson Stain (biopsy)
Phaeohyphomycosis• Representsabroadspectrumofdematiaceous(blackorpigmented)fungalinfectionsrangingfromsuperficialtodeeporganinvolvement.Organismsappearintissueasdarkyeast-like cells, pseudohyphae-like elements, variously shaped hyphae, often thick with swollen cell walls or any combination of these forms. All organisms look similar
• Fontana-MassonstainrevealsthepigmentthatmaybemissedwithH&E• Scleroticbodiesand/orgranulesareNOTseen• Needcultureforidentificationoforganism
Figure 7-24. Alternaria
Alternaria • Dark,septatehyphaewithlarge,brownconidiainchains.Lookslikeahandgrenade
Curvularia• Dark,septatehyphaewithlargeconidiacontainingusually4cellsappearcurveddueto
swelling of the central cell
Other Organisms• Exophiala, Bipolaris, Wangiella
Medical Mycology 281
Figure 7-25. Cryptococcosis Mucicarmine Stain (biopsy)
Cryptococcosis• Cryptococcus neoformans and Cryptococcus gatti - seen in immunocompetent patients
in tropics and recently in Northwest U.S. and Vancover• Encapsulatedyeast,polysaccharidecapsuleenhancespathogenicity• Ubiquitous,abundantinsoilenrichedwithagedpigeondroppingsandroostingareas,
moldy fruit, found in small numbers normal skin, vagina, GI tract• Bothvarietiesbecomeairborne• Normal host: Disease asymptomatic or mild pulmonary
infection• Primarycutaneouscryp.shouldberegardedasasentinelof
disseminated disease• PrevalenceinAIDS3-6%• Biopsy: Encapsulatedround,darkwalledyeastcell2-12µm.
May see single or multiple budding within a single capsule• Gelatinous pattern: Numerous organisms, minimal
inflammation• Granulomatous pattern: Fewer organisms, granulomas• The organism stains with PAS, GMS, and Fontana-Masson• Themucopolysaccharidecapsulestainswithmethyleneblue,alcianblue,andmucicarmine• India Ink:Goodscreeningmethod;highlightscapsuleoforganism,usefor“touchprep”of
lesion• Latex agglutination test: Measures circulating capsular antigen• Culture: Flat to heaped cream-colored colonies may be very mucoid• Treatment: Amphotericin B with/without flucytosine followed by fluconazole for
maintenance, itraconazole, fluconazole, voriconazole, posaconazole
Candidiasis• Candida albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. dubliniensis, C. kefyr• Mostcommonfungalopportunisticinfection,maybedifficulttoevaluate;yeastareubiquitousandpartofendogenousflora
• C. albicans and C. glabrata - most often isolated from patients with invasive candidiasis• Cutaneous and mucocutaneous candidiasis: All ages, most common in very young and
elderly, both sexes. Mucosal prevalent in HIV positive individuals
uTIPa HIV, immunocompromised patients:
dissemination to CNS, bone, skin.
Cutaneous findings occur 10-15%;
disseminated disease may occur
without pulmonary or CNS symptoms.
Lesions most often found head, neck,
mouth, nose and are polymorphous:
nodules, papules, ulcers, herpetiform,
cellulitis, molluscum-like, acneiform
282 2011/2012 Dermatology In-Review l Committed to Your Future
• Clinical manifestations include: Thrush, perleche, vulvovaginitis, balanitis, paronychia, onychomycosis, intertrigo, folliculitis, congenital and neonatal candidiasis, systemic dissemination to any organ
• Cutaneous lesions: Papulonectrotic eschars, purpura• Biopsy: Budding yeast, pseudohyphae, some species
produce true hyphae• Topical treatment: Topical azoles, nystatin, terbinafine,
naftine• Systemic treatment: Amphotericin B, ketoconazole, fluconazole, itraconazole, voriconazole,
caspofungin• Culture: Cream colored pasty colony, growth 2-5 days
C. albicans• Mostcommonspecies50%-60%ofcandidainfections• Trueandpseudohyphae
C. glabrata• 15%-20%ofcandidainfections• Fluconazoleresistance
C. parapsilosis• Chronicparonychiaand systemic infections
C. tropicalis • 6-12%• Frequentlycausesdisseminationtoskin.Major cause of septicemia and disseminated
candidiasis especially in patients with leukemia, lymphoma, and diabetes
C. dubliniensis• ImplicatedinoropharyngealCandidiasisinHIVinfectedpatientsandmostfrequently
implicated in cases of recurrent infection following antifungal drug treatment
7.7 MISCELLANEOUS ORGANISMS CAUSING FUNGUS-LIKE INFECTIONSRhinosporidiosis
• Rhinosporidium seeberi, anaquaticprotozoanpreviouslyconsideredafungus• MainlyinIndia,SouthAmerica,Africa,rarelyseeninU.S.• Largepolyps,granulomatous,wart-likelesionsmostfrequentlyinnasalmucosa,eye,mouth
• Biopsy: Spherulesorsporangium~250-350µm, endospores appear rough like raspberries• Stainsredwithmucicarmine• Theorganismisnotculturable• Differential diagnosis: Cryptococcus, mucormycosis, paracoccidioidomycosis, Alternaria,
Aspergillus• Treatment: Surgical removal, dapsone, local amphotericin B injection
uTIPa Factors contributing to candida infection:
impaired epithelial cellbarrier, systemic ill-
ness, neutrophil and macrophage
disorders, immune disorders, therapeutic
agents, congenital or acquired endo-
crine disorders, malignancies, indwelling
catheters, hyperalimentation, heat,
humidity and friction
Medical Mycology 283
Figure 7-26. Protothecosis (biopsy)
Protothecosis• Prototheca wickerhamii• Rarecutaneous,subcutaneous,systemicinfectionscausebyachloricalgae• Worldwide habitat: Stagnant water• Skinlesionsgenerallyseeninimmunosuppressedpatientsaftertrauma:papules,plaques,
vesicles, cellulitis, eczematoid dermatitis, verrucous nodules• Causesolecrenonbursitis1/3cases
• Biopsy: Stains well with PAS or GMS, round to oval nonbudding spherules (sporangia), with prominent cell walls, found free or in giant cells.Mature form contains a symmetrical arrangement of endospores = morula, 8-20 µm (“soccer ball”)(Figure 7-21)
• Culture: Creamy white colonies, growth 3 days at 30º C• Roundsporangiacontainingendospores,nobudding,andnohyphae• Treatment: Surgicalexcision,AmphotericinB+/-tetracycline,ketoconazole
7.8 RANDOM FACTS AND SUMMARY TABLEUmbilicated Lesions Seen In
• Cryptococcosis• Histoplasmosis• Penicilliosis• Coccidioidomycosis
Organisms Found Engulfed by Macrophages → “His Girl Penelope”• Histoplasmosis• Granuloma Inguinale• Rhinoscleroma• Leishmaniasis• Penicilliosis
Organisms that are Angiotrophic and Angioinvasive
• Aspergillus sp.
• Fusarium sp.
• Zygomycetes
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Table7-6.SummaryofOrganismSizeandAppearanceinTissueCondition Diameter of Organism (µm) Features
Lymphocyte 8-10 Point of Reference
Actinomycotic mycetoma 150-290 Granule containing thin filaments
Eumycoticmycetoma 500-2000 Granule containing hyphae and chlamydoconidia
Aspergillosis 2-4 Septate hyphae
Mucormycosis 10-25 BroadInfrequentlyseptateirregular hyphae
Blastomycosis 8-15 Broad-based budding yeast
Coccidioidomycosis 10-80 Spherule (organisms 2-5 um)
Histoplasmosis 3 Yeast, no capsule
Paracoccidioidomycosis <60 Mariner’s wheel
Penicilliosis 2-4 Ovaltoroundyeastwithcrosswalls
Cryptococcosis 4-20 Mucinous encapsulated yeast
Protothecosis 6-10 Spherule, Morula (soccer ball)
Rhinosporidiosis 250-350 Spherule (organisms 6-10 um)
Sporotrichosis 4-6 Round to cigar-shaped yeast
Chromoblastomycosis 6-12 Copper pennies, medlar bodies, sclerotic bodies
REFERENCES1. Espinel-Ingroff,A.Invitroactivitiesofthenewtriazolevorconazole(UK-109,496)againstopportunisticfila-
mentous and dimorphic fungi and common emerging yeast pathogens. J Clin Microbiol 1998;36:198-202.2. HayRJ.DeepFungalInfections.InTBFitzpatricketal.,Eds.Dermatology in General Medicine 5th ed. New
York: McGraw Hill, vol II, 2372-2388, 1999.3. Kane,JR,etal.Laboratory Handbook of Dermatophytes. Belmont, CA: Star Publishing, 1997.4. Kwong-Chung,KJ,Bennett,JE.Medical Mycology.Philadephia:LeaandFebiger,1992.5. Larone,DH.Medically Important Fungi: A Guide to Identification.4thed.Washington,DC:ASMPress,2002.6. LionakisMS,KentoyiannisDP.FusariumInfectionsinCriticallyIllPatients. Semin Respir Crit Med2004;25(2):
159-169.7. McGinnis, MR. Chromoblastomycosis and phaeohyphomycosis: new concepts, diagnosis, and mycology.
J Am Acad Dermatol1983;1-16.8. Pfaller,MA,etal.Invitroactivityoftwoechinocandinderivatives,LY303366andMK-0991(L-743,792),
against clincial isolates of Aspergillus, Fusarium, Rhizopus, and other filamentous fungi. Diagn Microbiol Infect Dis1998;30:251-255.
9. Rippon,JW.Medical Mycology: the Pathogenic Fungi and the Pathogenic Actinomycetes. 3rd ed. Philadelphia:WBSaunders,1988.
10. SoberaJO,ElewskiBE.FungalDisease.InBologniaJL,JorizzoJL,RapiniRPEds.Dermatology 2nd ed. 1135-1161, 2008.
11. Sullivan, D, Coleman D. Candida dubliniensis: characteristics and identification. J Clin Microbiol1998;36:329-334.
12. VarkeyJB,PerfectJR.RareandEmergingFungalPulmonaryInfections.Semin Respir Crit Care Med 29 (2): 121-131, 2008.
13. Weitzman,I,Padhye,AA.Dermatophytes,GrossandMicroscopic.Derm Clinics1996;14:9-22.14. Ellis,David.“Mycologyonline”2011.TheUniversityofAdelaide,Australia.March13,2011<http://www.mycol-
ogy.adelaide.edu.au/>.
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