Pityriasis alba is a common mild dermatitis inflammation of round or oval slightly scaly patches which leave pale hypopigmented marks after the inflammation has faded.

Pityriasis alba affects mainly children, and some young adults, especially on the cheeks and upper arms. It is common in patients with eczema.

It becomes most apparent in summer, particularly in children with darker skin, because these are areas which have not tanned.

The areas of inflamed skin don't develop a tan while the surrounding skin does. This gives the appearance of paleness to the skin.

The color eventually evens out over several months. It is rarely permanent.