Definition: Keratosis (plural
is keratoses), is a skin condition characterized by an overgrowth
of horny skin layers. There are 3 major kinds of keratosis.
Actinic Keratosis: Overgrowth of outer skin
layers caused by long-term overexposure to the Sun. Keratosis
Follicularis: Uncommon hereditary disorder characterized
by dark, sometimes purulent (containing pus) patches. Treatment
includes vitamin A orally and topically, and sometimes with
corticosteroids. Seborrheic Keratosis: Condition
marked by well-curcumscribed wartlike lesions that are often
itchy and covered with a greasy crust and occur most often
on the face, neck, upper chest, and upper back. Treatment
is by curettage, cyrotheraphy, or electrodesication.
Keratosis on the palm and inner fingers
Keratosis follicularis (same individual
as in bottom two pictures)