Conditions of the skin appendages See also: Category:Conditions of the skin appendages Conditions of the skin appendages are those affecting the glands of the skin, hair , nails , and arrector pili muscles. [ 1 ] Acne necrotica Acquired generalized hypertrichosis (Acquired hypertrichosis lanuginosa) Acquired perforating dermatosis (Acquired perforating collagenosis) Acrokeratosis