What is pseudochromhidrosis?
Pseudochromhidrosis is the discolouration of normal colourless sweat by an exogenous agent on the skin surface.
Who gets pseudochromhidrosis?
Pseudochromhidrosis is rarely reported, affecting all age-groups, and may involve family members simultaneously.
What causes pseudochromhidrosis?
In pseudochromhidrosis, the sweat can become discoloured by chromogenic bacteria and fungi including:
- Serratia marcescens has been associated with pink-red sweat
- Pseudomonas aeruginosa has been associated with green-blue sweat
- Corynebacterium has been associated with black-brown sweat
- Bacillus cereus and other Bacillus species have been associated with blue sweat
- Malassezia furfur has been associated with blue sweat.
Examples of coloured chemicals or dyes on the skin surface causing pseudochromhidrosis include:
- Yellow staining is often seen on pale clothing worn near the axillae due to the aluminium in antiperspirants mixing with sweat
- Self-tanning lotion can stain sweat brown
- Fabric dyes in clothing.
What are the clinical features of pseudochromhidrosis?
Pseudochromhidrosis can affect any body area, however face, neck and palms are the most commonly involved sites.
The colour of the sweat depends on the underlying chromogen or dye. The stain may be seen on the skin or clothing, and can be removed with a moistened wipe or alcohol swab.
Pseudochromhidrosis is usually asymptomatic but may cause embarrassment for the patient.
What is the differential diagnosis of pseudochromhidrosis?
How is pseudochromhidrosis diagnosed?
Pseudochromatosis is diagnosed by taking a thorough history and checking for any possible contact on the skin with chemicals, dyes, and coloured clothing. Check for possible risk factors for skin infection.
The diagnosis may be supported by:
- Fungal and bacterial cultures revealing chromogenic bacteria and fungi
- Normal findings on skin biopsy
- Wood lamp examination - may be positive if infection is due to porphyrin-producing bacteria
- Normal results of liver and kidney function tests excluding jaundice and uraemia.
What is the treatment of pseudochromhidrosis?
Pseudochromhidrosis is easily treatable as it is due to an extrinsic cause.
Treatment is most commonly with antiseptic soap and/or antibiotics including topical clindamycin, topical and/or oral erythromycin for 1 to 2 weeks, even when culture-negative. Any predisposing cause for the infection, such as use of a topical steroid, should be ceased.
When an exogenous chemical or dye has been identified as the cause, avoidance quickly resolves the condition.
What is the prognosis for pseudochromhidrosis?
Pseudochromhidrosis resolves once the cause has been identified and removed or treated.