A rash that develops under the breast, or on the chest, may result from skin irritation or an allergic reaction. Other causes can include infections and skin conditions, such as eczema and psoriasis.
In this article, we describe some of the causes of a rash under the breast and the options for treatment. We also cover when to see a doctor.
Eczema, or atopic dermatitis, is a long-term autoimmune condition that typically affects children but can also occur in adults.
Eczema causes patches of skin to become:
- itchy
- red
- dry, cracked, or scaly
- sore
The rash can develop on any part of the body, but it usually affects the hands, elbows, knees, and face.
It can also occur in folds of skin, such as under the breasts or where the legs meet the buttocks. Symptoms tend to come and go, and the severity varies from person to person.
Doctors do not fully understand what causes eczema, but certain things seem to trigger symptoms in some people. Common triggers include:
- soaps
- detergents
- particular foods
- stress
- weather
Treatments for eczema include moisturizing creams, or emollients, as well as topical steroids and antihistamines. It helps to avoid contact with known triggers.
Heat rash occurs when sweat gland ducts in the skin become blocked and the sweat flows back into the gland.
Other names for heat rash include miliaria, sweat rash, and prickly heat.
Heat rash typically consists of small red spots, which may feel itchy, prickly, or swollen.
The condition is common in newborns because their sweat glands have not yet fully developed, but it can occur in anyone.
Heat rash results from excessive sweating, and causes can include:
- hot, humid weather
- wearing heavy or nonbreathable clothing
- intense exercise or physical activity
- fever
People can relieve symptoms of heat rash with cold compresses, cool showers, calamine lotion, and mild steroid creams.
Contact dermatitis is a type of eczema that occurs when the skin comes into contact with a specific allergen or irritant.
It typically causes an itchy, red rash that may also be swollen, dry, and blistered. Depending on the type of reaction, this rash may develop almost immediately or take several hours or days to appear.
Common triggers of contact dermatitis include:
- soaps, detergents, and disinfectants
- plants, such as poison ivy
- cosmetics, perfumes, and toiletries
- jewelry
- chemicals and solvents
Treatment of contact dermatitis depends on the cause and the type of reaction, but it can include emollients, antihistamines, and topical and oral steroids. It also helps to avoid known triggers.
Hives, or urticaria, is an itchy rash of red bumps or welts that can develop anywhere on the skin, including under the breast. The bumps usually blanch, or turn white, when a person presses on them.
Hives is often a result of an allergic reaction. Triggers can include:
- foods, such as nuts, shellfish, and milk
- medications, such as certain antibiotics and aspirin
- insect bites and stings
- latex
- animal dander
- dust mites
- pollen
- plants
Hives can also be a symptom of anaphylaxis — a severe and potentially life-threatening type of allergic reaction that requires immediate medical attention. Other symptoms of anaphylaxis can include:
- trouble breathing or wheezing
- swelling of the face, hands, and feet
- nausea and vomiting
- fainting, dizziness, or loss of consciousness
Additional issues that can cause hives include:
- bacterial and viral infections
- emotional stress
- physical triggers, such as pressure, temperature, sun exposure, and exercise
Treatment for hives includes antihistamine medications and avoiding known triggers. For people with severe or persistent hives, a doctor may prescribe steroids or refer them to a dermatologist.
Psoriasis is a chronic skin disorder that causes thick patches of red, scaly, and itchy skin. These patches can develop anywhere on the body, but they often appear on the elbows, knees, lower back, hands, and face.
There are several types of psoriasis, each with their own characteristics, and the severity can vary from person to person. Symptoms of psoriasis often flare then reduce for a time.
Inverse psoriasis is the most common type that develops under the breast. The rash is characterized by smooth, red patches of skin in the folds of the body.
Inverse psoriasis often occurs under the breasts, or in the armpits or the groin area. It does not usually cause the flaky patches that develop with other types of psoriasis.
Treatment options can include topical medications, light therapy, and systemic or biologic drugs.
Scabies is a condition that occurs when parasitic mites burrow into the skin. The main symptom is an itchy rash of tiny red spots. The itching tends to be worse at night, and scratching the rash can cause sores.
The rash can develop on any part of the body, but the burrow marks tend to appear in areas such as:
- the skin between the fingers and toes
- skin folds under the breast
- the nipples
- the wrists, palms, elbows, and armpits
- the waist or belt line
- the head, face, or neck
- the soles of the feet in infants and children
- the groin area and buttocks
Scabies is contagious, and there are no effective over-the-counter medications for treating it, so it is important to seek medical attention. A doctor can prescribe medicated creams or lotions to kill the mites and relieve symptoms.
Cellulitis is a bacterial infection of the deep layers of skin and the tissues beneath them. It usually occurs in the breast, rather than on the skin underneath it, but cellulitis can make the breast appear and feel:
- red
- swollen
- hot
- tender
- painful
Other symptoms can include:
- pus-filled blisters
- fatigue
- fever or chills
- nausea and vomiting
- dizziness
- confusion
Symptoms of this infection can come on suddenly and progress quickly. People with symptoms of cellulitis should seek immediate medical attention. Severe infections can spread to other parts of the body and become life-threatening.
Doctors treat cellulitis with antibiotics, which a person may need to take for 7–14 days. Though symptoms usually improve within a few days of treatment, it is important to complete the full course of antibiotics.
Some viral infections can cause a rash under the breast. They include:
Chickenpox
Chickenpox, or varicella, results from infection with the varicella-zoster virus. It is a highly contagious disease.
Chickenpox typically starts out as an itchy, red, spotty rash on the chest, back, and face, rather than under the breasts. Over the course of several days, these spots develop into fluid-filled blisters that eventually scab over.
Other symptoms can include:
- fever
- headache
- fatigue
- loss of appetite
- aching muscles
Learn more about chickenpox here.
Shingles
Shingles, or herpes zoster, is a painful rash that typically develops as a single stripe on one side of the body, such as under one breast.
The rash usually lasts for
Some people experience severe pain, tingling, or itching in the affected area before the rash appears. Other symptoms of shingles can include:
- headache
- fever and chills
- generally feeling unwell
Anyone who has ever had chickenpox can develop shingles later in life. Shingles can occur at any age, but it is more common in
Doctors may prescribe antiviral drugs or pain medications for people with shingles. Some at-home treatments include calamine lotion, wet compresses, and oatmeal baths.
See a doctor for any rash that is severe, persistent, painful, or recurrent. Also, consult a doctor if the rash occurs along with other worrisome symptoms such as fever, nausea, or vomiting.
Rashes, such as hives, can also be a symptom of anaphylaxis, which is a potentially life-threatening allergic reaction that requires immediate medical assistance.
If a person also has any of the following symptoms, call 911 or take them to the emergency room:
- trouble breathing or wheezing
- swelling of the face, hands, and feet
- nausea and vomiting
- fainting, dizziness, or loss of consciousness
Rashes that develop under the breast often result from skin irritation or allergic reactions.
However, rashes on the chest region can also stem from infections such as shingles, cellulitis, measles, chickenpox, and scarlet fever. Some other possible causes include psoriasis, eczema, and heat rash.
People with rashes that are severe, recurrent, or occur with other worrisome symptoms should see a doctor, such as a dermatologist. Seek immediate medical attention if the rash accompanies other possible symptoms of anaphylaxis.