Finding a bump in your armpit can be a surprising and sometimes concerning discovery. Many people experience this at some point, and the immediate thought often turns to worry. While armpit bumps are frequently harmless and resolve on their own, they can occasionally signal a more significant underlying health issue. Understanding the potential reasons behind these bumps can help you know when to seek further guidance.
Why Armpits Are Prone to Bumps
The armpit (axilla) is a complex area with structures that can become inflamed, infected, or enlarged, leading to bumps. It houses numerous lymph nodes, small, bean-shaped glands of the immune system. These nodes filter lymph fluid, trapping bacteria, viruses, and foreign particles. When fighting infection or reacting to stimuli, lymph nodes can swell and become noticeable.
The armpit is also rich in sweat glands (apocrine and eccrine) and hair follicles. Apocrine sweat glands are associated with hair follicles in areas like the armpits. These glands produce sweat that, when broken down by bacteria, can contribute to body odor. Both hair follicles and sweat glands can become blocked or infected, leading to localized swelling and bumps.
Common Causes of Armpit Bumps
Several common conditions can lead to the appearance of an armpit bump, each with distinct characteristics.
Swollen Lymph Nodes
Swollen lymph nodes are a frequent cause, often indicating the body is responding to an infection, such as a viral illness like the flu or mononucleosis, or a bacterial infection. They can feel tender or rubbery and may move slightly when touched. Vaccinations, like those for COVID-19, can also temporarily cause lymph node swelling as the immune system reacts.
Ingrown Hairs
Ingrown hairs occur when a hair curls back or grows sideways into the skin, often after shaving or waxing. They can cause red, itchy bumps that may become painful or infected.
Cysts
Cysts are non-cancerous sacs filled with fluid or material under the skin. They grow slowly and can be painless or painful.
Folliculitis
Folliculitis is an inflammation of hair follicles, appearing as small, red, pimple-like bumps that can be itchy or tender. It results from a bacterial or fungal infection.
Hidradenitis Suppurativa (HS)
Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition where hair follicles become blocked and inflamed, leading to painful lumps, abscesses, and sometimes tunnels under the skin. Bumps can rupture, leaking pus and blood, often in areas where skin rubs together, like the armpits.
Lipomas
Lipomas are benign fatty tumors that grow slowly under the skin. They are soft, rubbery, and usually painless.
Allergic Reactions
Allergic reactions, often from deodorants or antiperspirants, can cause localized irritation, redness, and swelling in the armpit. This type of bump subsides once the irritant is removed.
When to Seek Medical Attention
While many armpit bumps are harmless, certain signs warrant a visit to a healthcare professional for evaluation. You should consult a doctor if the bump persists for more than a few weeks without improvement or if it continues to grow larger. A bump that feels hard, is fixed in place, or has an irregular shape should also be evaluated.
Medical attention is also advised if the bump is accompanied by other concerning symptoms, such as persistent fever, night sweats, or unexplained weight loss. Any bump that causes significant pain, rapidly changes in size or color, or causes discomfort should be examined by a healthcare provider to determine its cause.
What to Expect at the Doctor’s and Treatment Options
When you visit a doctor for an armpit bump, they will begin with a physical examination and ask about your medical history. They will inquire about when you first noticed the bump, any changes in its size or appearance, and whether it is painful or associated with other symptoms. The doctor may gently feel the lump to assess its size, consistency, and tenderness.
Depending on the initial assessment, your doctor may recommend further diagnostic tests. These could include blood tests to check for signs of infection or inflammation. Imaging tests, such as an ultrasound or mammogram, might be ordered to visualize the lump’s internal structure and its relation to surrounding tissues. In some cases, a biopsy, which involves taking a small tissue sample from the lump for microscopic examination, may be performed for a definitive diagnosis.
Treatment approaches vary based on the underlying cause of the armpit bump. For bacterial infections, oral antibiotics are prescribed to reduce the lump’s size within days. Cysts or abscesses may benefit from warm compresses to encourage drainage, or a doctor may need to drain them. If inflammation is the primary issue, corticosteroids might be used, while benign growths like lipomas or uncomfortable cysts can be surgically removed. For many harmless bumps, watchful waiting and monitoring for any changes may be the recommended approach.