Tinea Versicolor

Etiopathogenesis - The Yeast Beast

• Causative Agent: Malassezia species (esp. M. globosa, M. furfur).
  • Dimorphic, lipophilic yeast; part of normal skin flora.
  • Disease occurs with conversion from yeast to mycelial (hyphal) form.
• Pathophysiology of Pigmentary Changes:
  • Metabolites interfere with melanin production:
    • Azelaic acid: Inhibits tyrosinase → hypopigmentation.
    • Malassezin: Induces melanocyte apoptosis.
    • Pityriacitrin: UV-filtering.
• Predisposing Factors:
  • Hot/humid climate, oily skin, hyperhidrosis.
  • Immunosuppression, corticosteroids, malnutrition, genetic predisposition.

⭐ Malassezia globosa is the most common species implicated in tinea versicolor.

Clinical Features - Patchwork Skin

• Lesions:
  • Well-demarcated macules and patches.
  • Variable pigmentation: hypopigmented (most common), hyperpigmented, or erythematous.
  • Fine, 'branny' or 'cigarette paper' scale.
  • Positive Besnier's sign (also Zireli's sign or 'coup d'ongle' sign): scaling accentuated by stretching or scratching the lesion.
• Distribution:
  • Typically affects seborrheic areas: upper trunk (chest, back), neck, upper arms.
  • Can involve face (especially in children) and intertriginous areas (axillae, groin).
• Symptoms:
  • Usually asymptomatic.
  • Mild pruritus may occur, often exacerbated by sweating.
  • Affected areas fail to tan with sun exposure, making hypopigmented lesions more apparent.

⭐ The term 'versicolor' refers to the ability of the lesions to present with various colors (pink, tan, brown, white).

Diagnosis - Spotting the Spots

• Wood's Lamp Examination:
  • Characteristic pale yellow to yellow-green fluorescence (due to pteridines).
  • May be negative in some cases or after washing.
• KOH Microscopy (10-20% KOH):
  • Pathognomonic 'spaghetti and meatballs' appearance: short hyphae & yeast clusters. 📌 'Spaghetti and Meatballs'.
  • 

  ⭐ The 'spaghetti and meatballs' appearance on KOH mount is diagnostic for tinea versicolor.

• Skin Biopsy: Rarely needed; shows fungal elements in stratum corneum.
• Fungal Culture: Not routine; Malassezia is lipophilic, requires special media (e.g., Dixon's agar).

Differential Diagnosis - Ruling Out Lookalikes

Key differentials are compared below. Also consider: Pityriasis rosea, Secondary syphilis, Progressive macular hypomelanosis.

Management - Banishing the Blemish

• Topical Therapy (Localized): First-line.
  • Selenium sulfide (2.5% lotion/shampoo)
  • Ketoconazole (2% shampoo/cream)
  • Zinc pyrithione shampoo
  • Ciclopirox olamine
  • Terbinafine solution/cream (less effective for Malassezia)
• Systemic Therapy (Extensive/Recurrent/Refractory/Topical Failure):
  • Fluconazole: 300-400 mg single dose OR 150-300 mg weekly for 2-4 weeks.
  • Itraconazole: 200 mg daily for 5-7 days.
• Prophylactic Therapy (Recurrent Cases):
  • E.g., Ketoconazole shampoo once or twice weekly.
• Patient Education:
  • Explain chronicity and high recurrence rates.
  • Pigmentary changes resolve slowly (months) even after mycological cure.

⭐ Pigmentary changes in tinea versicolor can persist for several months even after successful eradication of the fungus.

High‑Yield Points - ⚡ Biggest Takeaways

• Caused by Malassezia spp. (lipophilic yeast, normal skin flora).
• Presents as hypo- or hyperpigmented macules/patches, often on the trunk and upper arms.
• KOH mount classically shows "spaghetti and meatballs" (short hyphae and spores).
• Wood's lamp examination reveals yellow-gold fluorescence of affected areas.
• Treatment: topical antifungals (ketoconazole, selenium sulfide); oral antifungals for extensive disease.
• Recurrence is common, particularly in warm, humid climates; prophylactic therapy may be needed.