When the bacteria are suppressed by antibiotics the pityrosporum yeasts can over grow. The rash consists of tiny itchy dome-shaped pink papules with an intermingling of small pustules. The spots are located mainly on the upper back, shoulders and chest. Sometimes spots are found on the forearms, back of the hands, lower legs and face. The tendency to scratch spots is greatest on the forearms, face and scalp.
Most patients have oily skins.
Most patients seek advice because of the itch. This may have lead their doctors to suspect scabies or other mite infestations. The itch tends to come in episodes, accompanied by a stinging sensation. Some patients notice the itch is worse after sweat-inducing exercise or after a hot shower. When scratched, the spots may display a local hive-like reaction with a surrounding red flare.