Find the word definition

WordNet
pityriasis alba

n. common form of pityriasis (usually in children or young adults) characterized by round patches of depigmentation

Wikipedia
Pityriasis alba

Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer creams.

The condition is so named for the fine scaly appearance initially present ( pityriasis) and the pallor of the patches that develop (while "alba" is Latin for white, the patches in this condition are not totally depigmented).