1. Differentiation of anemic nevus: Anemic nevus is a kind of congenital hypochromic spot, which mostly exists at birth, because the capillaries at the spot are less than normal skin, so the skin does not become red or white when rubbing the affected area, and the surrounding skin becomes red.
2.Non-pigmented nevus, which develops after birth or soon after birth, is often distributed along the nerve segment, showing local or generalized hypochromic spots with blurred boundaries and jagged edges and no surrounding pigment.
3.Pemphigus foliaceus, mostly occurs in the hot weather season, caused by fungal infection, positive fungal examination.
4. Pityriasis simplex, mostly occurs in children with white spots on the face, rough surface, and negative Wood’s lamp examination.
5.Discoid lupus erythematosus occurs mostly in adults, especially in the cheeks and lips, with white atrophy and dilated capillaries, and sometimes also found with adhesive scales, enlarged hair follicle mouth and keratin plugs.
6.Geriatric leukoplakia, middle-aged and above, common in the elderly. The white spots are round, generally rice to bean size white spots, slightly depressed, not fused. Mostly occurs in the chest and back, extremities, does not occur in the face, adolescent children do not develop.