label: Ochronosis
label_lc: ochronosis
description: Brown or blue-gray discoloration of the skin that can present on the axillary and inguinal areas, face, palms or soles. In addition, blue-black discoloration can be apparent on skin overlying cartilage in which the pigment is deposited, such as the ears. This is a characteristic manifestation of alkaptonuria, which is an autosomal recessively inherited deficiency of homogentisic acid oxidase that results in accumulation of homogentisic acid in collagenous structures. The sclerae are also typically involved.