Annular lesions, in images

Tinea versicolor

This commonly presents with multiple well-demarcated, oval or round macules covered in a fine scale mainly over the trunk and chest. These can be pale and become more obvious after tanning of surrounding skin on exposure to the sun. Sometimes, they can be dark in colour. It is caused by a Malassezia fungus that is normally present and symptomless on human skin. Patients are usually otherwise healthy but a warm humid atmosphere, immunosuppression, treatment with a corticosteroid, and the application of oily preparations can be factors in its development. It commonly occurs when sebaceous glands are more active, between 15 and 24 years old but is rare in the elderly. The diagnosis is a clinical one but it fluoresces yellow or green under a Wood's lamp. Treatment includes a topical imidazole cream or ketoconazole shampoo lathered, applied and washed off after three to five minutes daily for five days. Diluted selenium shampoo can also be used in this way. For non-responsive or widespread cases, prescribe 200mg of itraconazole daily for one week. The skin will take some months to regain its normal colour.