Definition of Keratosis pilaris

Keratosis pilaris: Small rough bumps, generally on the face, upper arms, and thighs.

Keratosis refers to a localized overgrowth of the upper layer of skin. Pilaris pertains to the hair. In keratosis pilaris, the buildup of keratin (the hard protein in the skin, nails, and hair) is limited to the hair follicles.