Skin and Soft Tissue

Kristine Krafts, M.D.June 6, 2008

Infections

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles• abscess• superficial fungal infections• deeper fungal infections

Skin and Soft Tissue Infections

BACTERIA

Gram-positive

Cocci• Staphylococcus• Streptococcus

Rods• Bacillus• Clostridium• Actinomyces• Corynebacterium• Listeria

Gram-negative

Cocci• Neisseria

Rods• A sh*tload

Weird• mycobacterium• spirochetes• chlamydia• rickettsiae• mycoplasma

• Bad infections• cellulitis

Skin and Soft Tissue Infections

• Infection of skin with some extension into subcutaneous tissues

• Most common location: extremities

• Strep pyogenes, Staph aureus

• Rarely, Clostridium perfringens (bad)

Cellulitis

Things you must know

• Venous/lymphatic compromise

• Diabetes

• Alcoholism

Cellulitis

Predisposing factors

• Swelling, erythema, warmth

• Lymphangitis, tender lymphadenopathy

• Maybe ringworm or psoriasis

• Maybe systemic symptoms

Cellulitis

Symptoms

Cellulitis

Cellulitis

• Strep pyogenes

• Staph aureus

• Haemophilus influenzae

• Clostridium perfringens

Cellulitis

Cause

• Erysipelas

• Clostridial cellulitis

• Nonclostridial anaerobic cellulitis

Cellulitis

Special forms of cellulitis

• Erysipelas• painful, bright red, swollen skin• Streptococcus pyogenes• kids, elderly• legs, face

Cellulitis

Special forms of cellulitis

Erysipelas

• Erysipelas

• Clostridial cellulitis• Local trauma, surgery• Gas in skin• Need surgical exploration

Cellulitis

Special forms of cellulitis

• Erysipelas

• Clostridial cellulitis

• Nonclostridial anaerobic cellulitis• Diabetes • Gas in skin• Foul odor• Need surgical exploration

Cellulitis

Special forms of cellulitis

• Bad infections• cellulitis• necrotizing fasciitis

Skin and Soft Tissue Infections

• Infection of fascia and fat; may spare skin

• Follows trauma (often mild)

• Strep pyogenes

• Often fatal

Necrotizing Fasciitis

Things you must know

Necrotizing fasciitis

• Diabetes-associated• mixed flora• feet → leg fascia

Necrotizing Fasciitis

Special forms of necrotizing fasciitis

• Diabetes-associated

• Head and neck fasciitis• after surgery or dental work• Ludwig’s angina

Necrotizing Fasciitis

Special forms of necrotizing fasciitis

Ludwig’s angina

• Diabetes-associated

• Head and neck fasciitis

• Fournier’s gangrene• Extension into GI/urethral mucosa• Aggressive• Severe pain

Necrotizing Fasciitis

Special forms of necrotizing fasciitis

Fournier’s gangrene

Fournier’s gangrene

Fournier’s gangrene after debridement

• Unexplained, excruciating, increasing pain

• Erythema

• In 1-2 days: erythema darkens; bullae appear

• Fever, myalgias, anorexia, hypotension

Necrotizing Fasciitis

Symptoms

Early necrotizing fasciitis

Necrotizing fasciitis

Necrotizing fasciitis 9 days later

Necrotizing fasciitis 16 days later

• Treat aggressively with repeated surgical debridement, antibiotics, fluid replacement

• Can spread to multiple organ systems

• High mortality

Necrotizing Fasciitis

Clinical course

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

Skin and Soft Tissue Infections

• Uncommon infection of muscle

• Develops rapidly

• Clostridium

• Often fatal

Necrotizing Myositis

Things you must know

• Clostridium perfringens• Deep, penetrating injury• Bowel surgery• Post-abortion with retained placenta

• Clostridium septicum• Non-traumatic• May enter through GI

Necrotizing Myositis

Etiology

• Organisms injected into tissue

• Tissue damage → anaerobic environment

• Necrosis starts within 36 hours

• Clostridial toxins cause damage• theta toxin: vessel injury• alpha toxin: heart injury, cell lysis

Necrotizing Myositis

Pathophysiology

• Sudden, severe pain

• Bronze, then purple-red skin

• Bullae and crepitus (gas)

• Systemic signs

Necrotizing Myositis

Symptoms

Necrotizing myositis

Necrotizing myositis

• Aggressive surgical debridement

• IV antibiotics

• Hyperbaric oxygen

• Fatal without early debridement

Necrotizing Myositis

Clinical course

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo

Skin and Soft Tissue Infections

• Superficial vesicopustular skin infection

• Children

• Face, extremities

• S. pyogenes, S. aureus

Impetigo

Things you must know

Impetigo

Impetigo

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis

Skin and Soft Tissue Infections

• Infection localized to hair follicles

• Multiple small pustules

• S. aureus, Pseudomonas

• Can lead to furunculosis

Folliculitis

Things you must know

Folliculitis

Folliculitis

Hot tub folliculitis

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles

Skin and Soft Tissue Infections

• Furuncle: infectious nodule around hair follicle

• Carbuncle: larger, subcutaneous abscess

• S. aureus

• Can be dangerous

Furuncles and Carbuncles

Things you must know

“The bourgeoisie

shall remember my boils!”

Furuncle

Carbuncles

Carbuncle

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles• abscess

Skin and Soft Tissue Infections

• Localized infection of dermis, subcutaneum

• Arises from trauma, IV drug abuse

• S. aureus

• Bacteremia and distant infection can occur

Abscess

Things you must know

Staphylococcal abscess

Splinter hemorrhages in bacterial endocarditis

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles• abscess• superficial fungal infections

Skin and Soft Tissue Infections

• Slow-growing

• “Ringworm”

• Sharp margins

• Dermatophytes

Dermatophytoses

Things you must know

• Dermatophytes = molds that invade skin, other keratinized tissues

• Sources: humans, animals, soil

• Three genera• microsporum• trichophyton• epidermophyton

Dermatophytoses

Microsporum

Microsporum and trichophyton

Calcofluor white stain (Candida)

• Most classified by location• Hair: tinea capitis, barbae• Skin: pedis, cruris, corporis• Nails: unguium

• Some other unique types• Tinea nigra• Piedra

Dermatophytoses

Tinea corporis

Tinea corporis

Tinea corporis

Tinea cruris

Tinea pedis

Tinea nigra

Tinea nigra

Tinea nigra

Black piedra

White piedra

• Pink to yellow-brown macules on trunk/arms

• Hypo-/hyperpigmentation, scaling

• Malassezia furfur

• “Spaghetti and meatballs”

Tinea (Pityriasis) Versicolor

Things you must know

Tinea (pityriasis) versicolor

Tinea (pityriasis) versicolor

Tinea (pityriasis) versicolor

Malassezia furfur

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles• abscess• superficial fungal infections• deeper fungal infections

Skin and Soft Tissue Infections

• “Rose gardener’s disease”

• First: painless papule (hand)

• Then: open sore, lymphatic spread (nodules)

• Sporothrix shenckii

Sporotrichosis

Things you must know

Sporotrichosis

Sporotrichosis

Sporotrichosis

• Tropical disease

• Swelling, nodules, pus with “grains”

• “Madura foot”

• Fungi (many) or Nocardia

Mycetoma

Things you must know

Mycetoma

Mycetoma granules

Granule histology: tons of hyphae

• Bad infections• cellulitis• necrotizing fasciitis• necrotizing myositis

• Not-so-bad infections• impetigo• folliculitis• furuncles and carbuncles• abscess• superficial fungal infections• deeper fungal infections

Skin and Soft Tissue Infections