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8 Causes of Pink or Red Armpit Bumps

If you have bumps under your armpit, it is most likely a boil, cyst, skin abscess, folliculitis, or dermatitis.
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Written by
Lauren Levy, MD, FAAD.
Clinical Instructor , Mount Sinai Hospital, Department of Dermatology
Last updated January 5, 2021

Red armpit bump questionnaire

Use our free symptom checker to find out what's causing your bump.

Red armpit bump questionnaire

Use our free symptom checker to find out what's causing your bump.

Red armpit bump symptom checker

What's causing those bumps?

There are a lot of reasons you might have a pink or red bump under your armpit, but almost all point to some kind of irritation or infection of the skin. These may include an abscess, cyst, infection of hair follicles, or an allergic skin reaction.

Because your armpit is exposed to sweat, outside products (shaving and deodorant) and often covered tightly by clothing, it is the perfect environment for the skin and hair follicles to become irritated, clogged, or infected.

Most armpit bumps can be treated by avoiding products and using warm compresses.

Causes

1. Boil

Symptoms

  • Red or pink golf ball size bump in your armpit
  • Pain
  • Pus oozing from the skin

A boil or furuncle is an infected hair follicle. Bacteria, usually Staphylococcus aureus ( “staph”), can get into the hair follicle if there is open skin or irritation, which often occurs after shaving. They occur commonly in the armpit because it is a warm, moist, and dark area that bacteria can easily enter and grow.

Also, a razor blade may introduce bacteria into the skin and then spread the infection.

It is important to treat the boil since the infection can spread and lead to cellulitis (skin infection). In rare cases, it can get into the bloodstream causing a systemic infection. Use warm compresses or hot water soaks. Other treatments involve a physician cutting and draining the boil and sometimes antibiotics. Throw out any razor that was used to prevent a recurring infection.

Pro Tip

Many armpit bumps are acute—meaning that they happen fast and can get quite big and painful rapidly (like an inflamed cyst or boil), but there are many things your doctor can do to help it get better fast. —Dr. Lauren Levy

2. Carbuncle

Symptoms

  • Large painful red bumps in your armpit
  • Contains pus that may ooze from the skin

A carbuncle is a collection of boils that are connected underneath the skin. Like boils, they are caused by bacteria, often Staphylococcus aureus ( “staph”). Instead of one follicle becoming infected, several hair follicles are involved, leading to a larger collection of pus. These are often quite painful. In rare cases, you can get a fever.

These need to be treated by a doctor, who will cut into it to open and drain it. Warm compresses should be applied to the area to help with pus drainage. Your doctor will likely give you a course of oral antibiotics. Throw out any razor that was used to prevent a recurring infection.

3. Skin abscess

Symptoms

  • A painful red lesion that is often fluid-filled
  • Pus may ooze from the skin
  • Fever may occur

A skin abscess is a large pocket of pus that has formed just beneath the skin. Bacteria gets into your skin through a small cut or scratch, such as from shaving, and starts to multiply, forming a cavity. The body fights this infection with white blood cells, which kill some of the bacteria but also cause pus within the cavity. If you get a fever, it’s a sign of a more serious infection. See your doctor immediately.

Small abscesses might drain if you use warm compresses. However, most require drainage by a doctor and antibiotics.

Read more about skin abscesses.

Pro Tip

People often think that painful pink armpit bumps are cancer. Very few are actually cancer. The majority are cysts, boils, or abscesses. Cancer is usually not painful and will not go away on its own. —Dr. Levy

Red armpit bump questionnaire

Use our free symptom checker to find out what's causing your bump.

Red armpit bump symptom checker

4. Cyst

Symptoms

  • A bump (usually 1 to 2 cm in size) underneath the skin of your armpit
  • May become red and/or painful if infected or inflamed
  • Often time has a central opening which can ooze a white cheese-like material (keratin)

A cyst is a growth that forms under the skin. It has a sac and may contain fluid, skin cells, or debris known as keratin. They are not usually painful and can move slightly beneath the skin. They have a small central pore or opening to the skin, which can ooze a thick cheese-like material.

Cysts can become infected or inflamed causing redness, pain, and pus oozing from the opening.

Cysts do not have to be treated and can be left alone if the cyst is not irritating or bothersome. If you want it to be removed, a dermatologist can cut it out. If the cyst becomes infected, it can be cut open, drained, and treated with antibiotics.

A doctor may give you an injection of steroids to calm down the cyst if it becomes inflamed. Seek immediate treatment if the cyst becomes red and painful, or if a fever occurs as these are signs of an infected cyst.

5. Folliculitis

Symptoms

  • Numerous small (1 to 2 mm) pink or red bumps surrounding hair follicles
  • Itchy, painful, or burning in the armpit
  • Bump may leak white fluid or contain pus

Folliculitis is inflammation of the hair follicle. There are two main causes of folliculitis: an infection or an irritation. It can occur on any part of the body that has hair.

  • An infectious folliculitis is commonly caused by the bacteria Staphylococcus aureus (known as Staph). The bacteria enters the hair follicles through open skin and causes the bumps, which are often filled with pus. The area may become painful.
  • An irritant folliculitis occurs from chronic trauma of the hair follicle, causing inflammation surrounding the hair follicle without an infection. Instead of pus inside the bumps, there is often a clear liquid. The bumps can be painful, burning, or itchy.

Sometimes, folliculitis will resolve on its own. Stopping shaving and the use of products for several days can clear it up. Over-the-counter benzoyl peroxide wash can be used to help treat bacterial folliculitis. If it does not resolve or worsens, see a dermatologist. Treatment may include an oral or topical antibiotic or a topical steroid lotion.

Read more about folliculitis.

6. Ingrown hair

Symptoms

  • Small (1 to 2 mm) red or skin-colored bump surrounding a hair follicle in the armpit
  • May see a curled hair in the center of the bump

An ingrown hair occurs when a hair grows back into the skin instead of growing straight out of the follicle. This causes inflammation around the hair because your immune system reacts to it as a foreign object.

A bump forms surrounding the hair. There may be pus or other fluid inside the bump. Ingrown hairs are often caused by shaving against the hair follicle or shaving too often. Having thicker or curly hairs also makes you prone to ingrown hairs.

If you get one, stop shaving for several days. If you see a coiled hair in the bump, removing it can help the inflammation go away. Using an exfoliant wash with glycolic acid may also help it go away.

If the lump persists, you may need to see a dermatologist. People who have repeated ingrown hairs may benefit from laser hair removal. And when shaving resumes, always shave in the direction that the hair grows.

7. Contact dermatitis

Symptoms

  • Redness of the armpits
  • Itching or burning
  • Scale, peeling or scabbing of the armpit

Contact dermatitis is when the skin becomes red, scaly, and itchy after coming in contact with a product or allergen. You may also have scabs from itching of the area. Contact dermatitis can either be allergic or irritant, but they tend to look similar.

With allergic contact dermatitis, the skin reacts to an allergen. This could be metal from a razor, a preservative, or ingredient in a soap, shaving cream, body wash, deodorant, or fragrance. Sometimes, allergens in clothing dye or dry cleaning materials can cause this rash.

With irritant contact dermatitis, a product causes a rash because it is irritating to the skin, not from an allergic reaction. The rash can be itchy but is most often described as burning.

An irritant contact dermatitis may occur with certain prescription strength antiperspirants when applied to open or raw skin. The combination of sweat and rubbing on a rough fabric may also cause irritant dermatitis.

Treatment involves figuring out what the product or material causing the rash is and then avoiding it. When it is difficult to figure out the culprit, a dermatologist can perform patch testing to identify the allergen. Oral antihistamines can help control the itch. A barrier cream like zinc oxide can help with irritation. A doctor may prescribe a topical steroid to help the rash go away.

Read more about contact dermatitis.

Red armpit bump questionnaire

Use our free symptom checker to find out what's causing your bump.

Red armpit bump symptom checker

8. Yeast infection (candidiasis)

Symptoms

  • Red patch with surrounding red bumps in the armpit
  • Itching or burning
  • Foul smell

Candida (a yeast) grows in warm and moist environments, making the armpit a perfect location for this skin infection. This condition looks like a moist beefy red patch with small pus bumps surrounding the patch (often referred to as satellite lesions). There may be a foul odor. Those with diabetes and obesity are more prone to yeast infections. Another risk factor is completing a recent course of antibiotics.

It is treated with a topical or an oral antifungal. Razor blades should be thrown out to prevent spreading the infection.

Other possible causes

A number of conditions may also cause pink or red armpit bumps, though these are either rare or pink or red armpit bumps are not usually the defining symptom. They include:

  • Warts
  • Lymphadenopathy (swollen lymph node from infection or malignancy)
  • Fox-fordyce disease (blockage of sweat glands)
  • Inverse psoriasis
  • Hidradenitis Suppurativa
  • Pityriasis Rosea
  • Hailey-Hailey disease
  • Erythrasma (bacterial infection)

Dr. Rx

A product that you have been using for years can still cause an allergic reaction. It does not have to be a new product. So make sure you tell your doctor all products, old and new, that you use. —Dr. Levy

When to call the doctor

You should call your doctor if you have any of these signs:

  • Persistent lesions
  • Fever
  • Pain
  • Itch
  • Spreading of the bumps

Should I go to the ER for pink or red armpit bumps?

You should go to the emergency department if you have any of these signs of an infection:

  • Fever
  • Weakness
  • Severe pain
  • Spreading redness in the area

Treatments

At-home care

  • Stop using all products on your skin in the area of the bumps.
  • Stop shaving for a few days until bumps go away.
  • Use warm compresses if there is a large lump in the area to promote drainage.

Other treatment options

Your doctor may recommend any of the following treatments:

  • Incision and drainage in the doctor’s office.
  • Surgical removal in the doctor’s office.
  • Oral or topical antibiotics.
  • Topical steroids.
  • Patch testing for allergies.
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Clinical Instructor , Mount Sinai Hospital, Department of Dermatology
Dr. Levy is a board certified dermatologist specializing in medical derm with expertise in acne, rosacea, skin cancer, psoriasis, and skin manifestations of rheumatologic disease. Her undergraduate education was completed at the University of Pennsylvania where she graduated summa cum laude and was inducted into the Phi Beta Kappa honors society. She graduated with a distinction in research from t...
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