Ochronosis

A 58-year-old black woman sought evaluation of areas of increased pigmentation on her cheeks that had been present for many years. Bleaching agents did not lighten the area; new, non–nickel-containing eyeglass frames had no effect. A 3-week course of halobetasol cream failed to fade the hyperpigmentation.

A 4-mm punch biopsy performed by Drs Jonathan Crane and Ronald Benjamin and Patricia Hood, PA-C, of Wilmington, NC, confirmed ochronosis, a fairly uncommon disease. Endogenous ochronosis is most often triggered by alkaptonuria, an autosomal recessive disorder that results in a lack of renal and hepatic homogentisic acid oxidase. The absence of this catabolic enzyme causes excess homogentisic acid to be excreted in the urine and to accumulate as dark pigment in connective tissue.¹ These deposits of pigment can occur in the sclera, cartilage of the nose and ears, tendons, and skin.

In exogenous ochronosis, hyperpigmentation is caused by external triggers; the condition is not inherited and is not associated with systemic illness. The disorder is most often seen in blacks.² Medications-particularly antimalarial agents, such as chloroquine and hydroxychloroquine-are frequent culprits. Over-the-counter bleaching creams with 2% hydroquinone and prescribed topical bleaching agents with 4% hydroquinone can incite ochronosis.

In this patient, it is likely that an allergic reaction to the nickel in the eyeglass frames that continually rubbed her face caused post-traumatic hyperpigmentation. In an attempt to remove the discoloration, she applied the hydroquinone-containing bleaching cream, thereby unknowingly triggering ochronosis. Counsel your patients who apply bleaching agents to use these preparations for a limited period.

Ochronosis is difficult to treat. This patient was advised to stop using all bleaching agents; in addition, tretinoin cream, 0.025% applied nightly for 2½ months, was prescribed. Postinflammatory hyperpigmentation may be eased by topical retinoids.

REFERENCES:1. Champion JL, Burton FJG, Ebling FJG, eds. Rook/Wilkinson/Ebling Textbook of Dermatology. 5th ed. Oxford, England: Blackwell Scientific Publications; 1992.
2. Levin CY, Maibach H. Exogenous ochronosis. An update on clinical features, causative agents and treatment options. Am J Clin Dermatol. 2001;2:213-217.