What is bumpy scatttered skin condition called and what causes it?

Keratosis Pilaris: Keratosis pilaris is a common skin condition that causes rough patches and small, acne-like bumps, usually on the arms, thighs and buttocks. Keratosis pilaris bumps are usually white, sometimes red, and generally don't hurt or itch. Keratosis pilaris can be frustrating because it's difficult to treat. Prescription medications and self-care measures can improve this condition.