White chaff rash may spread and expand. White furfur is a mild inflammatory skin condition that develops on the face of children, and it is possible for it to spread. The cause of pityriasis alba, also known as facial pityriasis simplex, is unknown and may be related to Malassezia furfur infection. The main manifestation is a round or ovoid pigment loss spots, covered with dry fine chaff-like white flakes, the edge is not clear, can gradually expand or increase. White chaff rash can subside by itself, generally do not need special treatment. If the condition is more serious, it is necessary to go to the hospital in time, under the guidance of the doctor for treatment.