what causes little white bumps on upper arms?
Keratosis pilaris. Keratosis pilaris causes small bumps to appear on the upper arms, legs or buttocks. They usually don't hurt or itch. Keratosis pilaris (ker-uh-TOE-sis pih-LAIR-is) is a common, harmless skin condition that causes dry, rough patches and tiny bumps, usually on the upper arms, thighs, cheeks or buttocks ...