E' floccosum Conidia

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E. floccosum Conidia
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Superficial Mycoses

• Malassezia furfur
• Phaeoannelomyces werneckii
• Piedraia hortae
• Trichosporon beigelii

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Superficial mycoses

• Superficial mycoses are fungal infections of the
  outermost keratinized (cornfield?) layers of the
  skin or hair shaft resulting in essentially no
  pathological changes. No cellular immune
  response is elicited minimal humoral host
  response - IgA
• These mycoses are largely cosmetic involving skin
  pigmentation or forming nodules along distal hair
  shafts often asymptomatic host is unaware

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Tinea versicolor

• Synomyms Pityriasis versicolor, Pityriasis
  folliculitis, dermatomycosis furfuracea, and
  others
• Etiology Malassazia furfur complex
• gt7 lipophilic yeast species of Malassazia
• Pityrosporum species - ? Different critter or
  previous name for some currently recognized
  Malassazia species?

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Tinea versicolor

• Epidemiology
• Malassazia furfur complex organisms are common
  residents of human skin
• Most common in warm moist climates. Tropical
  areas can have prevalence lt 40. Most common
  during summer months in temperate areas.
• Classically a disease affecting young people
  around the pubertal time probably related with
  hormonal changes and increase in sebum secretion.
  However, children are not excluded from suffering
  this fungal infection.

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Tinea versicolor

• Clinical manifestations
• Unsightly circular lesions
• Dark or light pigmented - usually light on dark
  skin and dark and light skin terms hypo- and
  hyperpigmentation used. Versicolor means
  varying colors.
• Most often on chest, back, and neck
• The face is commonly affected in children with
  the forehead showing mostly hypopigmented
  macules.

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Tinea versicolor
Hyperpigmentation on light skin
Hypo- on dark skin
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Tinea versicolor

• Laboratory diagnosis
• KOH preparation performed on skin scrapings
• Microscopic findings include
• Curving septate hyphae with some branching
• Clusters of oval yeast with a few buds
• Often described and spaghetti and meatball in
  appearance

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Tinea versicolor
Cluster of Budding Yeast
Curvy Septate Hyphae
Spaghetti and Meatballs
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Tinea versicolor

• Laboratory diagnosis
• Culture is not necessary to establish the
  diagnosis
• Malassazia / Pityrosporum have a requirement for
  fat usually not present in SDA and other mycology
  media
• Can be grown on media supplemented with fat (such
  as overlaying the inoculated media with olive oil
  or using a whole milk based medium)