Trichomycosis is a mild bacterial infection that mainly affects the axilla, also referred to as the armpit. Other areas of the body, such as the scalp, genitals, or buttocks, can also be affected.

While the infection itself isn’t serious and often comes without any symptoms, it can be uncomfortable. How common the infection is isn't known since it is not often reported due to a lack of symptoms.

This article discusses symptoms and causes of trichomycosis, as well as how it is diagnosed and treated.

Trichomycosis Symptoms

While many people with trichomycosis experience no symptoms at all, symptoms can develop. The symptoms are not severe and can cause mild discomfort in the armpit area, the groin, or the area between the buttocks.

Signs of infection from trichomycosis include:

• Sweating in the area that can be yellow, black, or red
• Underarm odor
• Small masses formed around the hair shaft (can be red, yellow, or black, and look similar to beads)
• Hair that becomes rough in texture
• Hair loss, in rare cases

Trichomycosis isn’t severe or serious in nature, and there are no complications associated with the infection.

Causes

Trichomycosis is caused by a type of bacteria known as coryneform-actinomycetes. The bacterium is referred to in medical literature as Corynebacterium tenuis.

While the infection itself generally isn't passed from person to person, there are some risk factors that make it more likely for someone to get it. These risk factors include:

• Hyperhidrosis, or excessive sweating of the underarms
• Living in a humid environment, such as a tropical climate
• Poor personal hygiene
• Obesity

Diagnosis

Many people don’t notice they have trichomycosis, and diagnosing it doesn’t come with any specific test. Typically, your healthcare provider will conduct a physical exam to check for signs such as the red, yellow, and black bead-like nodules that appear on the hair shaft and other signs of infection.

If more information is needed to make a diagnosis, a solution of potassium hydroxide will be used to help determine if the bacterium is present on the body.

In some cases, a wood’s light exam will be used. This type of test utilizes ultraviolet light to identify the colonization of bacteria on the skin.

Treatment

Treating trichomycosis is a simple process that begins with shaving off the affected hair. Following the removal of hair, antibiotic creams, ointments, or powders may be used to help ensure that bacteria are eliminated from the area.

The antibiotic typically used is erythromycin. However, other types of antibiotics, such as clindamycin, may be used, as well as antifungal medication known as clotrimazole.

Summary

Trichomycosis is a mild infection of the hair under the armpit caused by Corynebacterium tenuis bacteria. While it typically presents with no symptoms at all, trichomycosis can cause the hair in the area to feel rough, and it can cause excessive sweating. Perspiration can be yellow, red, or black, the same color as the bead-like nodules that may form around the hair shaft in the affected area.

There are no serious side effects of the condition. The easiest way to diagnose it is by examining the area. Treatment involves shaving off the hair and possibly using antibiotic creams until the infection has cleared.

A Word From Verywell

People may have trichomycosis and not even know it. While it's scary to think you might have an infection and not be aware of it, having trichomycosis is not serious and doesn't do any harm to your health. If you suspect you have the infection, make an appointment with your healthcare provider. A provider will be able to diagnose the condition so you can begin easy and effective treatment.