Case of trichomycosis axillaris in a 35-year-old
A 35-year-old male patient came to the dermatology clinic with a 9-month history of white clumps on his axillary hairs. He had first spotted the deposits on his axillae and groyne hair. The pubic-hair involvement vanished after shaving, but the axillary hair anomalies persisted after daily washing with coconut-oil-based and antibacterial soaps and one shaving session. He noted no odour, soreness, or itchiness. White concretions around the hairs in both axillae (Panel A) were discovered during investigation. A Wood’s lamp examination revealed the concretions’ yellow-green fluorescence (Panel B), and dermoscopy revealed cottonlike formations on the hair shafts (Panel C).
The patient was diagnosed with trichomycosis axillaris. Trichomycosis axillaris is a superficial bacterial infection of the axillary hair; the name is misleading because it is caused by corynebacterium species rather than fungus. When bacteria combine with dried apocrine sweat, visible deposits accumulate on hair shafts, especially in the presence of hyperhidrosis or poor hygiene. The patient’s symptoms resolved after one week of treatment with topical clindamycin and a daily benzoyl peroxide wash.
Background
Trichomycosis axillaris is a benign superficial corynebacterial colonisation of the axillary hair shafts characterised by the presence of adhering granular concretions. Trichomycosis pubis is a condition in which the pubic hair is affected. The corynebacterial triad was named after a study showed the occurrence of erythrasma, trichomycosis axillaris, and pitted keratolysis.
Pathophysiology
Corynebacteria are gram-positive rods that form an important part of the cutaneous flora. Bacterial overgrowth is aided by a warm and damp local environment. Disease risk factors include hyperhidrosis and inadequate hygiene.
Clinical findings
The initial sign may be a rancid acid odour in the axillae. Axillary hair examination reveals 1-2mm yellow, red, or black granular nodules or concretions surrounding hair shafts. This gives the hairs the appearance of being beaded. These nodules are deeply embedded in the hair shaft and difficult to remove. Although red and black are the most common colours in tropical climes, yellow is the most common nodule colour.
There could be hyperhidrosis in the area, and sweat could be yellow, red, or black. There is no related hair fragility or alopecia, and no underlying skin pigmentation change. In a handful of cases, similar concretions can be detected on the pubic hair (trichomycosis pubis). On examination, other corynebacterial-related disorders such as pitted keratolysis and erythrasma (the so-called corynebacterial trifecta) may be found.
Several gram-positive Corynebacteria species cause Trichomycosis axillaris. A potassium hydroxide (KOH) preparation, followed by a light microscopy examination, will reveal the responsible bacteria in the concretions. A culture is not required. Under light microscopy, gramme stain will also reveal slender purple rods. Wood’s light investigation will reveal a fluorescence that is dull yellow or gray-white.
Diagnosis
Hair casts, piedra, pediculosis pubis, and artefacts from deodorants, lotions, soaps, or powders are all possible causes of trichomycosis axillaris. Microscopy and Wood’s light examination can help distinguish between these diseases.
Hair casts have an amorphous look and do not contain microorganisms. They move easily along the hair shaft.
A fungal infection known as white piedra can affect axillary hair. It manifests itself as white, cream-colored, or brown nodules that are easily removed from the hair shaft. White piedra has no fluorescence. Furthermore, the KOH test will detect encapsulated arthroconidia or blastoconidia rather than bacteria.
Pediculosis pubis (pubic lice, crabs) affects the pubic area, however it can also affect the axillary hairs in certain men. Nits, nymphs, and adult lice are identified using. a magnifying glass and can be easily removed with forceps.
Risk factors
Trichomycosis axillaris is a common condition all over the world. About 25% to 30% of adult males are diagnosed with the condition each year. Women are, however, less likely to be affected, maybe because of the frequent removal of hair from the axillary region. The most significant risk factors are axillary hyperhidrosis and inadequate hygiene. Warm temperatures and high humidity are other danger factors.
Source: NEJM
