When the lesions are scratched, a fine scale is apparent. This infection most commonly involves the upper trunk, but the arms, axillae, abdomen, and groin may also be affected. Most lesions fluoresce a yellowish color under a Wood's light. In folliculitis, inflammation of the hair follicle causes red papules and pustules that surround individual hairs. One cause of folliculitis, especially in young adults, is M. furfur .
Lesions appear predominantly on the trunk but occasionally on the arms as well.
The lack of comedones distinguishes the lesion from acne. Pruritus and stinging may be present. In patients with tinea versicolor, KOH preparations of scrapings from the lesions demonstrate pseudohyphae and yeasts, which resemble spaghetti and meatballs. This technique is sufficient to establish the diagnosis. The yeast form prevails in folliculitis and is easily seen on Gram's stain of purulent material from a pustule, appearing as a large, oval, gram-positive coccus that is much larger than bacteria.