What causes an underarm rash?
In most cases, a rash is a temporary symptom that is usually treatable with over-the-counter (OTC) medications and home remedies.
However, some rashes, such as long-lasting, returning, or severe rashes, may be a sign of underlying health conditions that require medical attention and treatment.
In this article, we examine different types of armpit rash and explain the treatment options for each one.
There are many different causes of armpit rash. The most common ones are listed below:
Eczema, heat rash, and chafing may cause armpit rashes.
When skin rubs hard against itself or clothing for too long, irritation is likely to occur. Areas of the body where the skin folds over itself or rubs against itself frequently, such as the armpit, are especially prone to chafing.
Chafing rashes are usually:
- raw, or with the top layer of skin rubbed off
- stinging and burning
- in streak formations, often with a lighter center streak
- swollen, cracked, and bleeding or crusted if severe
Many people experience underarm chafing while exercising or wearing clothing that does not fit them properly.
Many people also experience chafing during the spring and summer months because they sweat more in the heat and moist skin is quicker to irritate.
Heat can mix with sweat on the skin and cause an irritation rash commonly called heat rash.
In most cases, heat rash causes itchy patches of bumps that are:
- slightly raised
Many people develop heat rash in their armpits during the warmer months or while in hot climates because the armpits contain lots of sweat glands.
Contact dermatitis occurs when the skin or body comes into contact with an allergen or irritant, sparking an immune response. This allergic reaction usually develops within a few hours of exposure to allergens or irritants.
Contact dermatitis rashes are usually:
There are many different causes of contact dermatitis. Some of the most common include:
- chemicals found in cleaning detergents and personal care products
- food or environmental allergens
- insect stings or bites
Hair removal processes
Many people develop patches of tiny, red, painful bumps after shaving the underarms. These bumps are usually present in and around the hair follicles.
Around 30 percent of the American population, mostly young children and adolescents, have eczema.
Eczema patches are usually:
- prone to releasing clear fluid when scratched
Eczema rashes tend to last for more than a week. An armpit rash may occur alongside similar patches on other parts of the body, such as the elbows, back of the knees, and neck.
People with eczema may experience flare-ups during certain times of the year or when they are ill or experiencing stress.
Seborrheic dermatitis is a type of eczema that develops around oil-producing glands. It causes symptoms that are different to those of eczema.
Seborrheic dermatitis rashes are usually:
- greasy looking
- itchy and burning
The skin may also develop white or yellow flakes.
A type of yeast called Candida commonly causes fungal infections. Candida usually triggers a rash that is:
Ringworm is a prevalent type of fungal infection that causes a red or silver ring-like rash.
Ringworm rashes may also be:
- blistered or scabbed
Home remedies for armpit rashes
Coconut oil may help treat armpit rashes.
Most rashes that occur as a result of allergic reactions or general skin irritation respond well to home care. People with these types of rash can try the following remedies:
- Keeping the area cool and dry by wearing loose clothing and taking lukewarm showers.
- Staying out of the sun as much as possible and away from humid environments.
- Tapping or patting itchy skin gently instead of scratching it.
- Taking a lukewarm bath with added oatmeal, vinegar, salt, or baking soda.
- Applying unscented, glycerol-based moisturizers for dry, scaly rashes several times a day.
- Avoiding long periods of time in the water, including long showers or baths.
Some natural therapies and supplements may also help reduce or treat most armpit rashes, but it is worth noting that there is little scientific evidence supporting their use.
Alternative home remedies for treating armpit rashes include:
- coconut oil
- topical vitamin B-12
- sunflower oil
- cardiospernum, a type of vine available in ointment form
- acupressure, which involves applying pressure to specific points on the body
Several of the conditions that cause armpit rashes require treatment using OTC medications.
OTC remedies for allergic reactions and other skin irritations include:
- Applying OTC hydrocortisone creams (0.5–1.0 percent) several times a day for a few days.
- Taking antihistamine medications. Some of these contain ingredients that cause drowsiness, which may make it easier to sleep and thus discourage scratching.
- Using OTC calamine lotions or creams.
- Applying OTC antifungal creams, gels, or sprays to the area daily for 2 weeks, where Candida or ringworm infections are the cause of the rash.
Armpit rashes that appear as a result of chronic skin conditions often require medical treatment. However, in most cases, a doctor will recommend trying a mixture of OTC and at-home remedies before prescription medications.
Prescription treatment options for people with eczema include:
- topical steroid creams
- topical PDE4 inhibitors or calcineurin inhibitors
- phototherapy, using ultraviolet light to boost vitamin D production
- biologic medications that contain engineered versions of human immune proteins
People may choose to use only personal care and cleaning products that have the National Eczema Association's Seal of Acceptance.
Treatment options for people with seborrheic dermatitis include:
- applying OTC antifungal creams
- washing the area with products containing zinc pyrithione
- softening scaly patches every few days with exfoliating products
- using topical corticosteroids, prescription-grade antifungal creams, or nonsteroidal creams during flare-ups, according to directions
Fragrance-free personal care products can help prevent underarm rashes.
Understanding what causes armpit rashes may help to minimize their severity.
General tips for preventing underarm rashes include:
- identifying and avoiding allergens where possible
- using unscented and fragrance-free personal care products
- bathing regularly in lukewarm water but not for extended periods
- using anti-chafing powders when in warm weather or exercising
- wearing clothing and undergarments that fit properly
- washing clothing, bedding, and towels frequently
- washing the hands or body after being around soil, animals, and plants
- avoiding sharing towels, combs, or clothing with other people
- wearing loose clothing made of natural fibers in warm weather
- ensuring pets and farm animals have all their recommended vaccinations
With proper care, most armpit rashes do not cause any complications.
Without this care, however, scarring and infection may develop. Scarring from armpit rashes usually occurs when people scratch their rash too much or allow an infection to develop.
Chronic or severe rashes, or those that do not go away with basic treatment, tend to come with a broader range of complications.
For example, there is a long list of allergic conditions that relate to eczema, including asthma and allergic contact dermatitis. Also, severe or untreated fungal and bacterial infections can lead to life-threatening complications, including sepsis and organ failure.
When to see a doctor
People with a severe or chronic rash should always talk to a doctor as soon as possible to determine its cause and potential treatment options.
People with rashes that appear without an apparent cause or do not go away with primary treatment should also speak with a doctor.
Certain types of rashes are the result of serious medical conditions that require emergency treatment, such as severe infection or allergic reactions. These rashes are quite rare though.
Seek emergency medical care for rashes that:
- cover the entire body or most of it
- are accompanied by blisters or fever
- develop suddenly and spread rapidly
- are painful or swollen
- bleed, ooze, or release pus
- are around the genitals, mouth, or eyes
- accompany nausea, vomiting, diarrhea, or constipation
- are unresponsive to OTC or at-home remedies
- sit in areas of thickened, crusty, or scabbed skin
- are in the midst of painful, tender, swollen, or red skin
- occur alongside cold hands and feet
- appear when the body is shaking
- are present alongside a stiff neck
- accompany confusion or dizziness