The cause of pityriasis alba is unclear and may be related to Malassezia furfur infection, atopic dermatitis, and ultraviolet light exposure, with no apparent relationship to vitamin deficiency. Also known as pityriasis simplex, pityriasis alba is a chronic condition that has been suggested in some literature to be associated with Malassezia furfur infections, but no fungi or bacteria have been detected during testing. The main manifestation of pityriasis alba is hypopigmentation of the skin, and patients with atopic dermatitis may also show localized hypopigmentation in the clinic. Prolonged exposure to the sun will cause some skin irritation and even damage to the skin, which is also an important causative factor for the development of pityriasis alba. Vitamins belong to the necessary elements of human growth and development, can maintain the normal physiological function of the skin, but there is no obvious relationship with the white chaff rash. Since the cause of pityriasis alba is unknown, the specific situation needs to be analyzed by a doctor’s consultation and according to the time of the onset of the disease.