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InfectionYeastICD-10 B36.0

Pityriasis versicolor

Tinea versicolor · Malassezia versicolor infection

Pityriasis versicolor is a superficial cutaneous mycosis caused by overgrowth of skin commensal Malassezia spp. (formerly Pityrosporum). The yeasts switch to a hyphal form on lipid-rich skin, producing dyspigmented scaly macules on the trunk, upper arms and neck. It is among the most common DDx for hypo- or hyperpigmented patches in young adults and frequently mimics tinea, post-inflammatory dyspigmentation, vitiligo and early hypopigmented mycosis fungoides.

CurrentLast reviewed 16 May 2026
Clinical image of Pityriasis versicolor
Pityriasis versicolor. Image sourced from DermNet New Zealand. Used under CC BY-NC-ND 4.0. No endorsement implied.

Microbiology

  • Lipophilic commensal yeasts: Malassezia globosa (commonest), M. furfur, M. sympodialis, M. restricta.
  • Conversion from yeast → hyphal phase on lipid-rich skin (sebaceous areas) drives disease.
  • Triggers: humid warm climate / season, sweating, occlusive clothing, oily skin, oral contraceptives, immunosuppression (including ICI, ciclosporin), pregnancy.
  • Azelaic acid produced by Malassezia inhibits tyrosinase → hypopigmentation in tanned skin.

Clinical features

  • Multiple small (5-10 mm) coalescing macules; well-demarcated.
  • Variable colour:
    • Hypopigmented on tanned / Fitzpatrick III-VI skin.
    • Hyperpigmented / pinkish-tan on pale skin.
    • Erythematous in inflammatory phase.
  • Fine bran-like (furfuraceous) scale on stretching the skin ("Besnier sign").
  • Sites: upper chest, upper back, shoulders, neck, proximal arms; rarely face.
  • Chronic, recurrent; warm-weather flares.
  • Pruritus mild or absent.

Investigations

  • Clinical diagnosis usually sufficient.
  • Wood lamp: golden-yellow fluorescence in ~30%.
  • KOH microscopy: short hyphae with clusters of round yeasts ("spaghetti and meatballs").
  • Dermoscopy: thin scale within follicular ostia.
  • Reserve skin biopsy for atypical or refractory cases — PAS shows yeast / hyphae.

Differentials

  • Vitiligo — complete depigmentation, no scale, Wood lamp accentuates.
  • Hypopigmented mycosis fungoides — chronic, atrophic, in children / young adults of darker skin; biopsy.
  • Pityriasis alba — facial in children with atopic eczema.
  • Post-inflammatory hypopigmentation.
  • Tinea corporis — annular advancing edge.
  • Confluent and reticulated papillomatosis (Gougerot-Carteaud) — reticulate, intermammary.
  • Seborrhoeic dermatitis overlaps; Malassezia involved.

Management

  • Topical (first-line):
    • Ketoconazole 2% shampoo applied to wet skin, left 5-10 minutes, rinsed; daily for 5-7 days.
    • Selenium sulfide 2.5% lotion / shampoo.
    • Zinc pyrithione shampoo.
    • Topical azoles (clotrimazole, miconazole, ketoconazole cream) for limited disease.
  • Oral (extensive / refractory / recurrent):
    • Itraconazole 200 mg OD for 7 days.
    • Fluconazole 300 mg weekly for 2-4 weeks.
    • Avoid oral ketoconazole (hepatotoxicity).
  • Counsel:
    • Pigment change persists for weeks-months after fungal eradication (does not equal treatment failure).
    • Recurrence common (~60% at 2 years) — prophylactic ketoconazole shampoo monthly may help.

References

  1. Hald M et al. Evidence-based Danish guidelines for the treatment of Malassezia-related skin diseases. Acta Derm Venereol. 2015;95:12-19.
  2. Crespo Erchiga V, Florencio VD. Malassezia yeasts and pityriasis versicolor. Curr Opin Infect Dis. 2006;19:139-147.
  3. Gupta AK, Foley KA. Antifungal treatment for pityriasis versicolor. J Fungi (Basel). 2015;1:13-29.
  4. British Association of Dermatologists. Pityriasis versicolor — patient information leaflet. London: BAD; 2023.

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