A 28-year-old white man presented with a recent-onset rash that involved the upper arms. The patient was otherwise healthy, with no known allergies and no history of medication or chemical exposure. The physical examination revealed multiple, discrete, 1- to 4-cm, salmon-colored, round, slightly scaly patches on both arms. There was no evidence of lymphadenopathy.
This patient has typical tinea, or pityriasis, versicolor. Here the clinical diagnosis is so typical as to assure the correct diagnosis. When there is doubt (as there might be in several of the following cases), a potassium hydroxide(Drug information on potassium hydroxide) preparation of the surface scales can be performed to demonstrate hyphae.
Versicolor, meaning many colored, refers to the various hues this eruption may assume. In white skin, this superficial fungal disease, caused by saprophytic yeast forms in the genus Pityrosporum, often is salmon-orange. Scaling is typically fine. Subjective symptoms, such as pruritus, are characteristically either mild or absent. Areas of involvement vary in size from minuscule to extensive.
The disease has a predilection for the trunk (chest and upper back) and the upper arms.
Topical treatment alternatives are daily application of 2.5% selenium(Drug information on selenium) sulfide for 1 week or daily application for 5 to 10 minutes of 2% ketoconazole(Drug information on ketoconazole) shampoo for 3 consecutive days. Systemic options are detailed in the following pages.