Malassezia infection

Malassizia infection prepared by: Aras sulaiman A.supervised by: Dr. Asia A.

Introduction:

• Yeasts of the genus Malassezia (synonym: Pityrosporum)are obligatory or nonobligatory lipophilic, normal flora organisms of the skin of warm-blooded hosts.

• under appropriate conditions, they cause superficial infections of the skin and associated structures.

• The most commonly described human infection due to a member of the genus is pityriasis versicolor, a chronic, superficial disease of the stratum comeum layer of the epidermis containing the typical hyphal elements and yeast cells of Malassezia furfur in tissue .

• Malassezia yeasts were first described in the 19th century as budding yeasts found on the skin of patients with dandruff.

• They are named after Louis-Charles Malassez, a French scientist who identified the yeasts in the outer layer of the epidermis of patients with seborrheic dermatitis.

• The different Mal assezia species are distinguished based on their morphology, growth characteristics, enzyme activities, as well as by molecular methods . Malassezia are dimorphic fungi.

Distribution of Malassezia on normal skin • Malassezia are common lipid dependent fungi that

grow on the sebaceous areas of human skin, including the face, scalp, and upper trunk.

• Although Malassezia are a part of the normal human skin flora, they may also cause or exacerbate several skin diseases, including tinea versicolor, Pityrosporum folliculitis, and seborrheic dermatitis…

Scientific classification

Kingdom: Fungi

Division: Basidiomycota

Subdivision:Ustilaginomycotina

Class: Exobasidiomycetes

Order: Malasseziales

Family: Malasseziaceae

Genus: Malassezia

Scientific classification

Currently there are 11 recognized species:Malassezia dermatis Sugita et al., 2002.M. furfurM. globosaM. japonica Sugita et al., 2002. M. nanaM. obtusaM. pachydermatisM. restrictaM. slooffiaeM. sympodialisM. yamatoensis

Species

Description of the disease1- Pityriasis versicolor:• Pityriasis versicolor (PV) This is a chronic, superficial fungal

disease of the skin characterised by well-demarcated white, pink, beige, or brownish lesions, often combining.

• The colour varies according to the normal pigmentation of the patient, exposure of the area to sunlight, and the severity of the disease.

• The mycelial phase of the fungus is predominant in the lesions. M. globosa is the main species isolated from the lesions.

Etiological Agents: –  Various species of Malassezia: •  M. furfur •  M. globosa •  M. sympodialis •  M. sloofiae •  M. restricta

2-Dandruff• is excessive shedding of dead skin cells

(flakes) from the scalp in faster rate and in larger quantities than normal

• These flakes get trapped with oil, clump together and become noticeable

• The exact causes of dandruff are M. restricta

3-Seborrheic dermatitis

• Seborrheic dermatitis (SD): is a chronic dermatitis with greasy scales in seborrheic areas in children and adults.

• M. sympodialis and M. restricta are the Malassezia species found commonly in SD lesions.

4- Malassezia folliculitis

• : This is characterised by follicular papules and pustules localised to the back, chest and upper arms, sometimes the neck, and more seldom the face.

• These are itchy and often appear after sun exposure. Scrapings or biopsy specimens show numerous yeasts occluding the mouths of the infected follicules.

5-Fungaemia (Systemic infections caused by Malassezia).• Such patients may also develop small

embolic lesions in the lungs or other organs. • Diagnosis requires special culture media and

blood drawn back through the catheter is the preferred specimen. Culture of the catheter tip is also recommended

6-Confluent and reticulate papillomatosis

7-Neonatal cephalic pustulosis

• Previously considered as neonatal acne, it is a newly described benign clinical entity occurring in neonates. There is a non-follicular pustular eruption involving the face, neck and scalp.

8-Malassezia dermatitis in dogs

Risk factor Pregnancy Malnutrition Immunosuppression (including use of tumor

necrosis factor inhibitors) Oral contraception Excess heat and humidity (heavy clothing with

perspiration) Age: adolescents and young adults Skin: more common in people with naturally oily

or excessively sweaty skin

Diagnosis

• Morphology• Biochemical and cultural properties• Laboratory diagnosis

Treatment

• Ketoconazole

Selenium Sulfide for Dandruff and Seborrheic Dermatitis

Ciclopirox olamine cream

Miconazole Nitrate Cream

Tea Tree Oil Shampoo contains 2% pure Tea Tree Oil

Pyrithione Zinc 1%