Hi i do not think there are different stages in
pityriasis alba.pityriasis alba usually occurs in the children presents as hypopigmented patches over the both cheeks.it is mainly due to vitamin a defiency.
calcium deficiency and
iron deficiency..
Pityriasis alba can be cured by iron.vitamin a supplementation and calcium supplementation.it can be cured by momate ointment in the morning and tacrolimus ointment in the night..use of deworming agent like
albendazole also helps to treat it