Pityriasis Versicolor

The hypopigmentation characteristic of pityriasis versicolor results from azelaic acid — a Malassezia metabolite — competitively inhibiting tyrosinase, the enzyme required for melanin synthesis. Pityriasis versicolor is caused by Malassezia converting from its yeast form to the mycelial form and invading the stratum corneum. Pityriasis versicolor recurs in 60–80% of patients within the first and second year after a complete treatment course, indicating strong individual predisposition. Pityriasis versicolor presents as flaky, discolored patches that may be hypopigmented or hyperpigmented, most commonly on the upper trunk but also on the arms, neck, and face.