What is apocrine chromhidrosis?
Apocrine chromhidrosis is the production of coloured sweat by apocrine sweat glands.
Who gets apocrine chromhidrosis?
Apocrine chromhidrosis is rare. It usually starts after puberty once the apocrine glands have matured, but has also been reported in infants. Chromhidrosis occurs in both sexes.
What causes apocrine chromhidrosis?
Apocrine chromhidrosis is due to lipofuscin granules in the apocrine sweat glands. It is thought that lipofuscin is produced from the oxidation of unsaturated fatty acids within the gland. Higher levels of oxidation result in darker colours. It is unknown why this happens.
What are the clinical features of apocrine chromhidrosis?
Apocrine chromhidrosis presents with coloured sweat localised to the distribution of the apocrine glands in the axillae, on the face (particularly the cheeks), breast areolae, and anogenital regions.
Sweat may be coloured blue, black, green, brown, or yellow, depending on the oxidation state of the lipofuscin, staining the skin and clothing. It is noticed by the patient particularly after exercise or emotional stress, and can result in having to change clothing multiple times each day.
The secretion of coloured sweat can be preceded by a prickly sensation or warmth on the affected skin.
What is the differential diagnosis of apocrine chromhidrosis?
Pseudochromhidrosis is sweat that becomes discolored after it has been secreted. It is more common than chromhidrosis.
Eccrine chromhidrosis is the production of coloured sweat from the eccrine sweat glands.
How is apocrine chromhidrosis diagnosed?
Apocrine chromhidrosis is usually diagnosed clinically. The following may be used to confirm the diagnosis:
- Expression of sweat from the affected site may reveal coloured sweat that quickly dries
- Wood lamp examination may show yellow fluorescence
- Microscopy of freshly-expressed discolored sweat demonstrates the lipofuscin granules
- A skin biopsy confirms the diagnosis if PAS-positive lipofuscin pigment granules are found within the apical cells of apocrine glands.
Other tests may include:
- A skin scraping and culture to exclude the chromogenic bacteria of pseudochromhidrosis
- Liver function and kidney function tests to exclude hyperbilirubinaemia and uraemia.
What is the treatment of apocrine chromhidrosis?
Treatments that have had some success in apocrine chromhidrosis include:
- Topical capsaicin cream, which reduces substance P (a neurotransmitter important in the production of sweat in apocrine sweat glands)
- Botulinum toxin type A injections.
These treatments temporarily reduce apocrine sweating and the discoloration recurs as the effects on sweating wear off.
What is the outcome for apocrine chromhidrosis?
Apocrine chromhidrosis is a benign chronic condition. It slowly regresses with advancing age as the apocrine glands gradually become less active.