title: Diagnostic utility of dermatoscopy in hydroquinone-induced exogenous ochronosis.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Skin and Venereal Diseases, T.N.M.C. & B.Y.L. Nair Ch. Hospital, Mumbai, India.
authors.forename: Sunil N
authors.initials: SN
authors.lastname: Mishra
authors.forename: Rachita S
authors.initials: RS
authors.lastname: Dhurat
authors.forename: Deepal J
authors.initials: DJ
authors.lastname: Deshpande
authors.forename: Chitra S
authors.initials: CS
authors.lastname: Nayak
mesh_terms: D000328:Adult; D046169:Dermoscopy; D006801:Humans; D006873:Hydroquinones / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008548:Melanosis / Q000188:drug therapy; D009794:Ochronosis / Q000139:chemically induced* / Q000473:pathology*
chemical_list: D006873:Hydroquinones; C031927:hydroquinone