An armpit fungus is a ringworm infection which occurs on the skin of the axilla (armpit) causing itching, burning and darkening of the skin under the arms. Similar to fungal infections on other areas of the body, an armpit fungus can be persistent given the high moisture content (due to armpit sweat), low light (covered by clothing) and warmth (due to body heat).

What Causes an Armpit Fungus?

An armpit fungus is caused by skin fungi,  usually skin molds or dermatophytes, that consume the superficial layers of the skin. Medically, a skin mold is referred to as a tinea infection and a fungal infection of the armpit is known as tinea axillaris. However most armpit fungal infections may extend beyond just the area of the armpit to surrounding skin and it is common to refer to the infection as tinea corporis (fungal infection on the body) involving the axillae. A skin yeast or cutaneous candidiasis may also be responsible.

While an armpit fungus is caused by skin fungi, infection usually arises as a result of other predisposing factors that may cause breaks in the skin. In terms of an armpit fungus, local conditions are the main contributing factors which may initially cause an armpit rash that is then infected by a fungus. Often, an armpit fungus may occur as a result of secondary spread, where fungal strands or spores are transferred from other areas of the body due to scratching with the fingers or using a towel on both areas after bathing.

Armpit Rash

An armpit skin rash may vary from contact dermatitis to intertrigo which occurs as a result of abrasion or chaffing. The most common contributing factors to an armpit rash include sweat, scratching the armpits or a perfume allergy. Less commonly, eczema or atopic dermatitis may be the cause of an armpit rash as it predominantly occurs on the folds of the skin, including areas like the elbow and behind the knees. Any break or persistent inflammation of the skin makes it prone to a fungal infection.

1. Armpit Sweat

The armpits, like the feet, are a sweaty area of the body caused by the warmth (body heat) in these areas.  Due to the confined area and thick armpit hair, sweat may build up and cause irritation of the skin. An increase in naturally occurring skin bacteria in the armpits may further aggravate any rash in this area. In cases of hyperhidrosis or excessive perspiration, the increased sweat may cause peeling which affects the skin’s integrity to prevent infiltration and infection from outside pathogens.

2. Armpit Irritation

Irritation of the armpits is often due to a combination of factors including armpit sweat, armpit hair, other skin diseases and warm or tight clothing causing chaffing. Poor ventilation in the area adds to any irritation. Usually this causes itchy armpits with a burning sensation after vigorous scratching. The skin irritation is  often due to inflammation and the damaged skin is unable to maintain a protective barrier which allows a skin fungus to quickly infect the skin of the armpits.

3. Armpit Perfume Allergy

perfume_allergyPerfumes and deodorants are commonly used on the armpits to reduce body odor which often emanates from under the arms. Based on individual skin sensitivity, perfume or deodorants may cause contact dermatitis which is often noticed as an itching or burning sensation shortly after applying any of these applications. Anti-perspirant deodorants leave a powdery residue that adheres to the skin over long periods and this may further aggravate any dermatitis. Allergies to perfumes or deodorants results in inflammation of the skin and scratching the area may result in breaks in the skin. Perfumed soaps, shower gels and body creams or lotions may cause a similar reaction.

Signs and Symptoms of an Armpit Fungus

An armpit fungus usually presents similar to fungal infections elsewhere on the body.

  • Itching
  • Burning under the arms usually due to scratching excessively and the damage caused by fingernails.
  • Flakes or specks of skin noticeable on the clothing or after scratching.
  • Dark discoloration of the skin under the arms.
  • Musty body odor which may also be due to skin bacteria and poor ventilation.

Treatment for an Armpit Fungus

The treatment for an armpit fungus is similar to that of a skin fungal infection elsewhere on the body. Topical antifungal creams, lotions or gels are usually effective for eradicating any skin fungus and should be continued for 4 to 6 weeks. In severe cases, especially where there are persistent skin fungal infections, an oral antifungal may be necessary. If a skin rash is present, a corticosteroid cream may be necessary to reduce inflammation and ease itching.

It is important to discontinue any perfumed product that may be causing a skin rash. An antifungal powder may be useful in reducing sweat build up in the area while ensuring that the skin fungus does not reestablish itself in the affected area. Wear clothing that is loose and thin to allow for adequate ventilation to the area. While a fungal infection is an itchy skin condition, avoid scratching as far as possible. Microabrasions caused by scratching will allow the fungal infection to persist.

Darkening of the skin under the arms is often a cause for concern particularly in women due to cosmetic factors. The dark discoloration of the armpits occurs as a result of long term skin inflammation in addition to friction and irritation caused by scratching. Avoid using skin bleaching creams in order to lighten the skin as this may cause further inflammation. A mild corticosteroid will reduce inflammation and itching thereby allowing the affected area to heal.


References

  1. Dermatophyte Infections. American Academy of Family Physicians
  2. Tinea corporis of the axilla. DermAtlas
  3. Cutaneous Candidiasis. Mycology Online

Article reviewed by Dr. Greg. Last updated on June 26, 2013