Snapshot A 21-year-old man presents to his dermatologist for a rash on his face. He reports that there is no itch or pain associated with it. Although he spent a summer at the beach as a lifeguard and the rest of his face tanned, the area with the rash has not tanned, resulting in a white and yellow colored patches on his face. On physical exam, there are multiple yellow-white macules along his jawline and a large patch on his left cheek. There are also multiple similar patches on his trunk. A skin scraping and KOH preparation reveals tinea versicolor as a diagnosis. He is prescribed a medicated shampoo to use on his skin. Introduction Clinical definition very common cutaneous fungal infection login to view 2 more bullets Associated conditions seborrheic dermatitis Epidemiology Prevalence 30-40% in tropical climates 1-4% in temperate climates Demographics most common in adolescents and young adults Risk factors hot and humid weather excessive sweating immunosuppression Etiology Malassezia spp. formerly Pityrosporum Pathogenesis when there is excessive heat and moisture, there may be increased growth of Malassezia spp. compared with other normal flora Presentation Symptoms asymptomatic inability to tan in affected areas Physical exam macules and patches affecting the trunk, neck, and face login to view 7 more bullets Studies KOH preparation skin scrapings mixed with KOH short multibranching hyphae and budding cells login to view 1 more bullet Wood lamp examination affected areas fluoresce yellow to yellow-green < 50% sensitivity Differential Vitiligo affected areas also fluoresce lesions are depigmented Eczema Psoriasis Seborrheic dermatitis Treatment Medical topical treatment login to view 10 more bullets oral antifungals login to view 5 more bullets Complications Areas of discoloration may be permanent Prognosis Often recurs