The patches of<unk>  may last from 1 month to about one year, but commonly on the face last a year. However it is possible that the white patches may last for more than 1 year on the face.
Pityriasis alba
Alopecia mucinosa
Pityriasis rosea
Phytophotodermatitis
Ichthyosis acquisita
Pityriasis rubra pilaris
Pityriasis amiantacea
Alopecia universalis