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You may develop a rash under your breasts in a variety of instances, due to a number of factors. The causes behind these rashes can range from natural skin responses to more serious disorders.

Causes generally fall into five categories:

  • infections
  • allergies
  • autoimmune disorders
  • cancer
  • heat rash

Below we detail the main causes of rashes under the breasts, treatment options, and how to prevent the rashes from occurring.

Infections

The warm, moist skin under breasts is an ideal breeding ground for bacterial, fungal, and yeast infections.

Candidiasis

Candidiasis results from the same yeasts, or fungi, that cause vaginal yeast infections, oral thrush infections, and diaper rash. These fungal infections often occur in babies, people with illnesses that affect their immune system, and people taking antibiotics.

Candida yeasts thrive in the moist, warm environment of skin folds, such as under the breasts. They cause a rash that often develops uncomfortable blisters and small cracks. Like many other rashes, candidiasis can be itchy.

Antifungal creams can treat candidiasis. If the infection is more widespread, your doctor may prescribe antifungal medications taken by mouth. It’s also important to keep your skin dry.

Learn more about candidiasis of the skin here.

Ringworm

Ringworm has nothing to do with worms. It’s one of several types of fungal infections called tinea. Fungi are microscopic, single-cell organisms present in the air, soil, water, animals, and human body.

The types of fungi that cause ringworm and related skin conditions, such as athlete’s foot and jock itch, are parasites that feed on dead keratin. This is the protein that makes up your skin, nails, and hair. Ringworm appears as round, red patches of skin with a distinctive red ring.

Ringworm is highly contagious and often spreads via shared towels, sheets, and showers. You can even get it from your pets.

Over-the-counter or prescription antifungal creams are effective in treating ringworm.

Allergies

Hives are an allergic response to a range of substances, including:

Hives are red or skin-colored bumps that can become itchy. Hives can occur on any part of your skin.

A doctor will typically recommend antihistamines to treat hives. These drugs block histamines, the natural chemical in your skin that causes hives. You may also use cold compresses and topical preparations such as cortisone creams or calamine lotion.

You can find a great selection of antihistamines here.

If you get hives regularly, your doctor may recommend that you see an allergist. An allergist will determine what substances you’re allergic to so you can avoid the allergens in the future.

Autoimmune disorders

There are different autoimmune disorders that may cause a rash under your breast. Autoimmune disorders are chronic conditions that you cannot cure, but you can treat the symptoms.

Eczema

Patches of inflamed skin that itch severely are signs of eczema, or atopic dermatitis. Eczema can develop small, fluid-filled bumps that ooze and crust over.

On light skin, eczema often appears as red or pink lesions, while it may appear a dark brown, purple, or gray on darker skin. Over time, your skin can dry out and be prone to irritation and itching before it flares up again.

Although you may get eczema anywhere on your body, it’s most common on the following areas:

  • face
  • hands
  • feet
  • behind the knees
  • the inner surface of the elbow

There’s no cure for eczema. However, you can manage it by keeping your skin moisturized with fragrance-free moisturizers and using cortisone creams or gels to control the itching.

Eczema symptoms may be made worse by:

  • harsh soaps and detergents
  • wool
  • sweat
  • stress

Inverse psoriasis

Inverse psoriasis is a less common form of psoriasis, a chronic disease of the immune system. It typically involves smooth, discolored patches of skin in the folds of the body. The condition often occurs under the breasts, armpits, and groin area. Inverse psoriasis doesn’t usually have the flaky skin plaques associated with other types of psoriasis.

Steroid creams and gels are the first-line treatment for inverse psoriasis. Doctors may also recommend skin medications that suppress the immune system for more severe cases.

Pemphigus Vulgaris

Pemphigus vulgaris is an autoimmune skin disease that leads to blistering of the skin. It mainly occurs in older adults and can appear anywhere on the skin.

Pemphigus vulgaris can occur on the breast and result in irritated patches of skin in the area. The exact cause of the condition is unknown, and treatment will typically involve corticosteroid creams and other immuno-suppressive drugs to lessen symptoms and avoid remission.

Hyperhidrosis

Hyperhidrosis is a condition in which your body’s sweat glands produce more sweat than is needed to cool the body. On average, a person has 2-4 million sweat glands and sweats up to a quart of fluid per day. All that perspiration is a welcome mat for germs that cause infections. The cause of hyperhidrosis is unknown, but it tends to run in families.

To help prevent sweating, you may wish to use antiperspirants under the breasts. There are also body antiperspirants made for this purpose, and some are even available in powder form. If they don’t do the job, your doctor may prescribe a more powerful antiperspirant.

Botox injections and the removal of sweat glands via laser or traditional surgery are options for severe cases.

Hailey-Hailey disease

Hailey-Hailey disease is a rare inherited disorder that results in a persistent, blistering rash.

This can occur under the breasts, or in other areas such as:

  • the neck
  • between the buttocks
  • in the armpits and groin

The rash tends to come and go spontaneously. Over time, the skin can become tough and dry and may develop painful cracks.

People usually use corticosteroid ointments and antibiotics to treat Hailey-Hailey disease. Doctors may recommend oral corticosteroids, photodynamic light therapy, or laser therapy in more severe cases.

If you have Hailey-Hailey disease, your doctor will advise you to avoid situations that make you sweat, such as not wearing heavy clothing that doesn’t breathe and not exerting yourself in hot weather.

Cancer

Inflammatory breast cancer is a rare form of rapidly spreading cancer. Symptoms include:

  • skin discoloration
  • pitted skin
  • pimple-like rash
  • an inverted nipple that points inward rather than outward

Although this type of breast cancer is rare, it’s important to see your doctor promptly if you have these symptoms.

A combination of chemotherapy, surgery, and radiation therapy is the standard treatment for inflammatory breast cancer.

Heat rash

Heat rash can also lead to rashes under the breast. Heat rash occurs when your sweat glands become blocked, so you can’t sweat through the pores. Instead, the sweat pools under your skin, causing inflammation and a rash.

The best treatment is to cool off. Heat rash mainly happens when you sweat more than normal because of heat and humidity. Heat rash usually clears up without treatment.

Hidradenitis suppuritiva

Hidradenitis suppuritiva is a chronic skin condition that causes lesions and inflammation in the sweat glands. It primarily occurs due to blocked follicles and a resulting infection.

Hidradenitis suppuritiva can occur under the breasts and in other skin folds such as the armpits, groin, and anal regions. The cause of the condition is not known and mild cases can be treated with at-home remedies such as cold compresses and good hygiene practices.

The causes of rashes under the breast vary greatly in severity. Contact your doctor if you experience any of these symptoms alongside rashes:

  • You develop a fever, nausea, or vomiting.
  • The rash is extremely painful.
  • You see no improvement after using self-help measures for several days.
  • The rash has open sores that don’t heal.
  • You have symptoms of inflammatory breast cancer.

You should also see a doctor if, in addition to a rash, you have a chronic disease or compromised immune system.

A rash under the breast is rarely anything more than an annoyance that causes discomfort. By identifying the underlying cause of the rash and treating it accordingly, most rashes heal within a couple of weeks.

Most treatments will involve keeping the affected area clean, dry, and free from irritants. Depending on the underlying causes of your rash, doctors may recommend anti-inflammatory or steroid creams, oral antibiotics, and other treatments.

Tips for relief

There are some things you can do to help treat symptoms of a rash.

  • Skip wearing your bra as much as possible until the rash clears up.
  • When you do wear a bra, make sure it fits without binding. Avoid underwire bras.
  • Try a bra liner or mini pad to absorb moisture under the breasts.
  • Wear loose-fitting clothes made of fabrics that breathe, such as cotton and linen.
  • Use unscented soaps, lotions, and moisturizers.
  • Apply a cool compress to the affected area.
  • Calamine lotion can help reduce itching.
  • Drying powders such as Gold Bond Extra and Lady Anti Monkey Butt help prevent rashes. Corn starch is popular as a powder but can worsen some rashes, especially if a yeast infection causes them.

You may be able to prevent rashes from forming under your breasts.

Maintaining thorough personal hygiene may help reduce the risk of fungal infection. Keeping the skin under your breasts clean and dry can help prevent yeast-based rashes. Regular washing and not sharing towels or clothes may also help prevent ringworm.

You can also reduce the risk of allergic reactions by avoiding your known irritants and prevent heat rash by wearing loose-fitting clothes and staying cool in the heat.

When rashes under the breasts result from autoimmune diseases or cancer, treating the underlying condition is the best course of treatment and prevention.

Read this article in Spanish.