Abstract

Eccrine chromhidrosis is a rare condition characterized by pigmented sweat caused by a chromagen such as dyes, chemical agents, water-soluble drugs, or pigment-producing microorganisms. We present a case of a 67-year-old male with a several-year history of numerous (up to ten) blue-brown pinpoint macules on the cheeks. The clinical differential diagnosis included a possible angioma, blue nevus, or carbon tattoo. Histologic examination showed a unilocular cyst within superficial dermis containing pink-tan-brown pigmented debris. The cyst wall was lined by a few layers of bland, lightly eosinophilic cuboidal cells consistent with an eccrine hidrocystoma. Etiologically, chromhidrosis may be linked to infections with chromogenic microorganisms such as Bacillus spp. (blue), Corynebacterium spp. (brown-black), Serratia marcescens (red), or Pseudomonas aeruginosa (blue-green). Thus, gram and PAS stains were ordered, which, while negative, could not definitively rule out an infectious etiology. Additionally, since eccrine chromhidrosis may be linked to the glandular breakdown of dyes or water-soluble drugs, the possibility of a reaction to an ingested medication, occupational exposure, or the topical application of a skincare product was raised. In conclusion, eccrine chromhidrosis often conjures a wide array of clinical questions that may only be answered following careful histologic evaluation and knowledge of the many causes of this uncommon dermatologic condition.

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