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Clinical analysis, diagnosis, and treatment of a 48-year-old female Filipino with Riehl melanosis

Maria Jenina P. Aguado, MD, Elizabeth Ryan, MD, and Johannes F. Dayrit, MD, FPDS, FDSP



Pigmented contact dermatitis (PCD) is characterized by non-eczematous pigmentation associated with contact sensitizers, usually without any active or preceding pruritus and erythema. PCD was first described by Riehl, who identified patients with brown to gray facial pigmentation concentrated on the face most commonly associated with sensitizing chemical such as cosmetics, fragrances, and textiles.


Case Report

This is a case of a 48-year-old female Filipino who presents with blue-grey to brown patches on the forehead of 1-year duration with no significant pathologic history. Clinical examination, dermoscopy and histology were consistent with a variant of pigmented contact dermatitis known as Riehl melanosis. Since anamnesis was unremarkable, patch testing was done to identify the contact allergen triggering the symptom. Results obtained a positive reaction to nickel, potassium dichromate, and textile dye.



Treatment includes the elimination of trigger factors, hence the importance of patch testing in the investigation of its cause. Alongside adequate photoprotection, a combination treatment of 1,064 nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, 20% tricholoacetic acid (TCA) peel and oral retinoids, were found safe and effective in the management of facial melanosis. Three-dimensional imaging and dermoscopy
were utilized to obtain a more standard and objective pre- and post-treatment comparison.


  1. Shenoi S, Rao R. pigmented contact dermatitis. Indian J Dermatol Venereol Leprol. 2007; 73(5):285-287
  2. Costescu M, Ghiorghiscan R, Miulescu R, Grigore M, Coman OA, Georgescu SB. riehl melanosis triggered by cleaning agents. DermatoVenerol. 2017;62:25-33
  3. Anstey, AV. Disorders of Skin Colour. In: Burns T, Breatjnach S, Cox N, Griffiths C, editors. Rook’s Textbook of Dermatology, 8th ed. UK: Blackwell Publishing Ltd; 2010. 58.1-58.59
  4. Wang L, Xu A. four views of riehl’s melanosis: clinical appearance, dermoscopy, confocal microscopy and histopathology. J Eur Acad Dermatol Venereol. 2014; 28:1199-1206
  5. Tardan MP, Zug KA. Allergic Contact dermatitis. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K, eds. Fitzpatrick’s Dermatology in General Medicine. New York, NY: McGraw-Hill Companies, Inc; 2012.152-165
  6. Andersen KE, White IR, Goossens A. Allergens from the European Baseline Series. c2010 [cited 2011 January]. Available from https://
  7. Johansen JD, Aalto-Korte K, Agner T, Anderson, K, Bircher A, Bruze, M, et al. european society of contact dermatitis guideline for diagnostic patch testing – recommendations on best practice. Contact Derm. 2015:73(4):195-221
  8. Hye Rang On, Won Jin Honh, Mi Ryung Roh. low-pulse energy Q-switched Nd:YAG laser treatment for hair-dye-induced Riehl’s melanosis. J Cosmet Laser Ther. 2015; 17: 135-138
  9. Puri N. Efficacy of Modified Jessner’s Peel and 20% TCA versus 20% TCA Peel Alone for the Treatment of Acne Scars. J Cutan Aesthet Surg. 2015; 8(1):42-45
  10. Lenz CR, Aldrich SL. Effect of systemic isotretinoin treatment on melasma: a case study and literature review. Clin Dermatol J. 2019. 4 (3) 00018

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Clinical analysis, diagnosis, and treatment of a 48-year-old female Filipino with Riehl melanosis