Pityrosporum folliculitis is an acute, intensely pruritic eruption caused by Malassezia furfur, the causative organism of tinea versicolor. The condition frequently manifests as follicular papules and pustules on the upper trunk (ie, upper back and chest as well as shoulders) of young to middle-aged adults. It also can affect the face, especially on the forehead along the hairline, the neck, and scalp.

The condition is also seen frequently in the immunocompromised, including patients on chronic oral prednisone and those with diabetes. High heat, humidity, and occlusive clothing or personal care products predispose to the condition. Recent use of oral antibiotics is also a risk factor.

Underlying conditions include human immunodeficiency virus (HIV) infection, immunosuppressive therapy, antibiotic therapy, Down syndrome, and systemic candidiasis.