pityriasis%20(tinea)%20versicolor
PITYRIASIS (TINEA) VERSICOLOR
Pityriasis (Tinea) versicolor is a fungal infection caused by Malassezia furfur. It is benign, superficial, and localized to the stratum corneum.
It may present as chronic or recurrent infection and may occur in healthy individuals.
It is more common in summer than winter months.
It presents with multiple well-demarcated macules or patches and finely scaled plaques with hypopigmentation or hyperpigmentation, hence the term "versicolor".
Lesions are usually found on the upper trunk, chest, back and shoulders, and may extend toward the neck, face and arms.

Pityriasis%20(tinea)%20versicolor Diagnosis

Assessment

Considerations for a Dermatology referral:

  • Negative microscopy & unclear diagnosis
  • Extensive & severe infection
  • Treatment failure in primary care setting
  • Consideration of oral antifungal therapy in children <12 yr
  • Immunocompromised patients
  • Consideration of long-term antifungal prophylaxis

Laboratory Tests

  • Lab testing is not usually needed for the diagnosis
  • Consider doing microscopy if:
    • Diagnosis is unclear
    • Infection is unresponsive to the regular topical antifungals
    • Planning oral antifungal treatment

Microscopy

  • Potassium hydroxide (KOH) examination of skin scrapings should confirm the diagnosis
    • Scales or debris are examined under light microscope after adding a drop of 10-20% KOH solution
    • Short stubby hyphae & yeast cells will appear as the typical “spaghetti & meatballs” appearance
  • Calcofluor may be used but this technique requires utilization of fluorescence microscope
  • Malassezia species also stain well w/ periodic acid-schiff (PAS) or methenamine silver

Culture

  • Unnecessary for routine diagnosis
  • Difficult to grow Malassezia in standard mycological media

Wood’s Light Exam

  • May be used to detect subclinical lesions
  • However, yellowish to white fluorescence is indicative only in approximately 1/3 of cases
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