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PekkaAutio

Pityriasis Versicolor

In pityriasis versicolor, the rash is caused by exceptionally abundant growth of Malassezia yeast.
The reason why this lipophilic yeast fungus grows in large numbers in some patients is not known.
The condition is not contagious.

Fairly common in young adults
Irregular, mildly scaling maculae/patches are seen on the trunk (pictures ), neck and proximal parts of the limbs.
The colour varies from pale to brown, even "dirty" grey. On light skin the maculae/patches are brown, on tanned skin they are more light-coloured than the surrounding skin (picture ).

The clinical appearance is diagnostic.
Malassezia also grows on normal skin. Therefore fungal culture is of no benefit.
In microscopy of a scraped sample (methyl blue staining) the appearance of Malassezia is typical ("spaghetti and meatballs").

Local azoles (ketoconazole, miconazole, clotrimazole) as an ointment (recommended dosing 1-2 times daily for 1-3 weeks) or ketoconazole shampoo (application once daily for 5 days; also a shorter treatment, even a single dose, may be sufficient). Before the summer season ketoconazole may used, as a prophylactic treatment, once daily for 3 days.
Alternatively, the following may be used:
- selenium sulphide, ciclopiroxolamine or zinc pyrithione shampoo (application once daily for 5-10 minutes and then washed away, duration of treatment 1-2 weeks)
- terbinafine cream or spray (twice daily for one week)
If, in more severe cases, oral treatment is chosen, the alternatives are itraconazole 200 mg once daily for one week or fluconazole 50 mg once daily for 2-4 weeks or 300-400 mg once a week for 1-3 weeks.
- Oral terbinafine is inefficient for this condition.
Especially light maculae/patches may require months to heal even after successful treatment until the skin becomes tanned on exposure to sunlight.
Pityriasis versicolor should not be handled as a contagious disease. Treatment does not mean eradication but merely control of the skin colonisation.

Gupta AK, Lane D, Paquet M. Systematic review of systemic treatments for tinea versicolor and evidence-based dosing regimen recommendations. J Cutan Med Surg 2014;18(2):79-90. [PubMed]
Gupta AK, Lyons DC. Pityriasis versicolor: an update on pharmacological treatment options. Expert Opin Pharmacother 2014;15(12):1707-13. [PubMed]
Hald M, Arendrup MC, Svejgaard EL ym. Evidence-based Danish guidelines for the treatment of Malassezia-related skin diseases. Acta Derm Venereol 2015;95(1):12-9. [PubMed]
Lange DS, Richards HM, Guarnieri J ym. Ketoconazole 2% shampoo in the treatment of tinea versicolor: a multicenter, randomized, double-blind, placebo-controlled trial. J Am Acad Dermatol 1998;39(6):944-50. [PubMed]