[Brown facial pseudochromhidrosis in a child: A bacterial disease?]

Pseudochromhidrosis denotes the production of colourless sweat that acquires colour after coming into contact with exogenous factors such as dyes in clothing, chemicals or chromogenic microorganisms.

A 9-year-old girl presented with progressive brown pigmentation predominantly on the nose, forehead, perioral region and cheeks. It was easily removable by rubbing with a moist compress, leaving normal-coloured skin as well as brown pigment on the compress. The same pigmentation recurred within 2h. The patient was not using cosmetics. Bacteriological culture of samples taken by rubbing the skin in affected areas on the face was positive for commensal bacteria of the skin (Actinomyces viscosus, Staphylococcus epidermidis, Cutibacterium acnes and Streptococcus sanguinis). Antibiotic therapy achieved total resolution of symptoms.

Bacteria constitute the most frequent aetiology of pseudochromhidrosis. Where such a cutaneous condition exists, even in the absence of positive bacteriological testing, antibiotic therapy would seem to be indicated as a therapeutic test. Biopsy does not appear to be essential as a first-line approach where a bacterial cause is suspected, but it may be proposed in the event of resistance to antibiotics.