Diagnostic utility of dermatoscopy in hydroquinone-induced exogenous ochronosis

Authors


  • Funding sources: none.

  • Conflits of interest: none.

Dr Chitra S. Nayak, MD
Department of Skin & Venereal Diseases
Opd no. 14, 2nd floor
Opd building
T.N.M.C. & B.Y.L. Nair Ch. Hospital
Dr A.L Nair Road
Mumbai Central
Mumbai 400008
India
E-mail: chitra1202@yahoo.co.in

Abstract

Background  Hydroquinone is the preferred topical bleaching agent used in the treatment of melasma. The adverse effects of its chronic use are confetti-like depigmentation and exogenous ochronosis. Exogenous ochronosis manifests clinically with gray-brown or blue-black hyperpigmentation, as well as pinpoint hyperchromic caviar-like papules over the malar region. Dermatoscopic findings of ochronosis are unique and point towards a clue for its diagnosis.

Methods  Three cases of suspected hydroquinone-induced exogenous ochronosis while treating melasma were subjected to dermatoscopy and histopathology studies.

Results  Dermatoscopy in the areas of caviar-like hyperpigmentation revealed accentuation of the normal pseudo-rete of the facial skin with amorphous densely-pigmented structures obliterating some follicular opening and multiple thin, short arciform structures. On histopathological examination, curved ochre-colored structures, ‘banana-shaped’ fibers, were seen in the dermis of all patients.

Conclusion  Exogenous ochronosis is difficult to treat. Dermatologists should be able to differentiate it from melasma and immediately discontinue hydroquinone. Exogenous ochronosis has characteristic features on dermatoscopy which may obviate the need for an invasive procedure of biopsy for its diagnosis.

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