Hello,
Without examination, confirmation of a diagnosis is tough but it can be pityriasis versicolor or pityriasis alba. Pityriasis versicolor is caused by an overgrowth of a yeast fungus and is found mainly on sun
exposed areas. Pityriasis alba is a common hypopigmented dermatitis.This is a self-limited disorder that usually resolves by adulthood.Severe cases may benefit by Psoralen plus ultraviolet light A photochemotherapy (PUVA).
To confirm the diagnosis, please get it evaluated from a dermatologist.