Alkaptonuria

Abstract

We describe a case of a 70-year-old woman who had been using a skin-lightening cream containing hydroquinone for a previous diagnosis of melasma. She presented a hyperpigmentation predominantly on her cheeks and eyebrows. The biopsy showed deposition of yellow-brown globules in the dermis. A diagnosis of exogenous ochronosis was made. An attempt of treatment using a Q-switched Nd:YAG laser has been initiated recently.

Introduction

Exogenous ochronosis is a cutaneous disease resulting from long-term application of topical agents. Histological examination is characterized by yellow-brown pigment deposits in the papillary dermis. The casual agent must be avoided and improvement occurs slowly. Cryotherapy, trichloroacetic acid, tretinoin gel, Q-switched ruby laser, dermabrasion and C[O.sub.2] laser have been reported as treatment.

Case Report

We describe the case of an hispanic 70-year-old woman who had been using a skin-lightening cream containing hydroquinone 2% for almost 6 years for a previous diagnosis of melasma. The patient reported an asymptomatic 5-year history of a slowly developing bluish gray discoloration. Physical examination revealed a symmetrically distributed hyperpigmentation on the cheeks and eyebrows (Figures 1-2). She denied a familiar history of dyspigmentation or other systemic symptoms. The biopsy showed deposition of a collection of yellowish-brown globules (ochronotic pigment) in the dermis (Figure 3). Since she had no systemic signs of alkaptonuria (endogenous ochronosis), we made the diagnosis of exogenous ochronosis. We are using a Q-switched Neodimio laser as treatment, but results are not assessed yet.

There are 2 forms of ochronosis: exogenous and endogenous ochronosis forms. Endogenous ochronosis is a manifestation of alkaptonutia, a rare autosomal recessive metabolic disorder (1:25000). (1) It results from a deficiency of homogentisic acid oxidase that causes an excess of homogentisic acid which deposits in connective tissues. (1,3)

Exogenous ochronosis was first reported in 1906. (4) It is a cutaneous disease resulting from long-term application of topical agents, most commonly hydroquinones. The use of depigmenting agents for cosmetic purposes is a long-standing practice. The exogenous form is characterized by an asymptomatic blue-black hyperpigmentation on the face and on the sides and back of the neck. The etiology of this hyperpigmentation remains unknown. (5) Topical hydroquinone may inhibit homogentisic acid oxidase in the dermis, with the result of a local accumulation of homogentisic acid that polymerizes to form ochronotic pigment. (6,7) The ochronotic coloration most commonly results from the prolonged use of certain topical agents like hydroquinones, but it also occurs with the use of antimalarials (8) and products containing resorcinol, phenol, mercury, or picric acid. Most of the patients with exogenous ochronosis are black women, but it has been reported as well in hispanic and caucasic patients. Histological examination is characterized by yellow-brown (ochronotic) pigment deposits in the papillary dermis. Treatment of this condition is very difficult. The casual agent must be avoided and improvement occurs slowly. The effectiveness of a quality-switched (QS) 755-nm alexandrite laser in treating this condition has been reported, without untoward side effects. (9) Cryotherapy, trichloroacetic acid, tretinoin gel, Q-switched ruby laser, dermabrasion and C[O.sub.2] laser have been reported as well for treatment.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

References

1. Garcia SF, Egbert B, Swetter SM. Hereditary ochronosis: hyperpigmentated skin overlying cartilaginous structures. Cutis. 1999;63:337-338

2. Albers SE, Brozena SJ, Glass LF, Fenske NA: Alkaptonuria and ochronosis: case report and review. J Am Acad Dermatol. 1002;27:609-614

3. Odabas AR, Karakuzu A, Seluk Y, Erdem T, Cetinkaya R. Alkaptonuria: a case report. J Dermatol. 2001;28:158-160.

4. Pick L. Uber die Ochronose. Klin Wochenschr. 1906;43:478-80

5. Levin CY, Maibach H. Exogenous ochronosis. An update on clinical features, causative agents and treatment options. Am J Clin Dermatol. 2001;2:213-7

6. Karmer KE, et al. Exogenous ochronosis. J Am Acad Dermatol. 2000;42:869-871

7. Penneys ND. Ochronosislike pigmentation from hydroquinone bleaching creams. Arch Dermatol. 1985;121:1239

8. Bruce S, Tschen JA, Chow D. Exogenous ochronosis resulting from quinine injections. J Am Acad Dermatol. 1986;15:357-361

9. Bellew SG, Alster TS. Treatment of exogenous ochronosis with a Q-Switched Alexandrite (755 nm) Laser. Dermatol Surg. 2004; Apr;30:555-558

Address for Correspondence

M. Huerta Brogeras MD

Servicio de Dermatologia

Hospital Universitario Gregorio

Maranon

C/ Maiquez, no 7

Planta 1a pabellon de oncologia.

Secretaria de Dermatologia

28007 Madrid, Spain

M. Huerta Brogeras MD, M. Sanchez-Viera MD

Department of Dermatology University Hospital Gregorio Maranon, Madrid

COPYRIGHT 2006 Journal of Drugs in Dermatology, Inc.
COPYRIGHT 2006 Gale Group