W3 SUPERFICIAL MYCOSES

• Superficial Mycoses

  • Confined to outermost layer of skin or hair; stratum corneum of the epidermis
  • No tissue response, no inflammatory reaction
• Clinical Manifestations of Superficial Mycoses

  Skin

  • Discoloration or depigmentation, and scaling
  • Brown / black macular patches

  Hair shaft

  • Cement-like attachments
• Malassezia furfur

  • Disease associated: tinea versicolor / pityriasis versicolor
  • Patchy, scaling lesions
  • "Versicolor" = varying pigmentation
  • More evident during warm months
  • Sites of infection: face, chest, trunks, abdomen
  • Common skin colonizer; can also cause dandruff
• Risk Factors of Malassezia furfur

  • Persons receiving corticosteroid therapy
  • Genetic influence
  • Poor nutrition
  • Excessive sweating
• Other method for Malassezia furfur

  Wood's lamp = fluorescence
• Other Method for Malassezia furfur

  • Colony morphology: moist, smooth, cream colored
  • Fungal culture + olive oil
• Disease Associated with Piedraia hortae

  • Black piedra
  • Occurs only on the hair of the scalp
  • Hard, brown / black gritty nodules attached to hair shaft
  • Consists of asci with up to 8 ascospores
• Laboratory Diagnosis for Piedraia hortae

  • Place infected hairs in 10% to 20% KOH
  • Nodules may be crushed to reveal asci
  • Thick-walled rhomboid cells containing ascospores seen
  • Colony morphology on Sabourand Dextrose Agar (SDA): brown colonies
• Specific Species of the Trichosporan beigelii complex

  • Trichosporan asahii --> fatal disease in immunocompromised
  • Trichosporan mucoides --> meningitis
  • Apiotrichum mycotoxinoverans --> pulmonary disease in cystic fibrosis
  • Trichosporan ovoides
  • Trichosporan inkin
  • Trichosporan asteroides
  • Cutaneotrichosporan cutaneum
• Trichosporan beigelli complex

  • Occasionally found as normal flora
  • Disease associated: White Piedra
  • Occurs on the hair of the scalp, face, pubic region
  • Soft mycelial mat surrounding hair