A palpable mass or swelling in the armpit, medically known as the axillary region, can be a source of concern. While discovering a lump in this area can be unsettling, many armpit lumps are benign, meaning they are not harmful and often resolve on their own. However, in some cases, an armpit lump can indicate a more serious underlying health issue that requires medical attention.
Common Benign Causes
The armpit is home to various tissues, and many non-cancerous conditions can lead to the formation of a lump. Swollen lymph nodes are one of the most frequent reasons for an armpit lump. These small, bean-shaped structures are a vital part of the immune system, filtering foreign invaders like bacteria and viruses from the body. When the body fights an infection, such as a common cold, flu, or a localized skin infection, the lymph nodes in the armpit can swell as they work to trap and destroy pathogens.
Cysts are another common benign cause of armpit lumps. These are typically harmless, fluid-filled sacs that can develop under the skin. Sebaceous cysts, for instance, form when a sebaceous gland becomes blocked, leading to a buildup of sebum. These cysts are usually soft to the touch and can vary in size.
Lipomas are benign fatty tumors, appearing as soft, movable, painless lumps. Consisting of fat cells, they are generally harmless and often require no treatment unless bothersome.
Inflamed hair follicles or ingrown hairs (folliculitis) can cause painful armpit lumps, especially after shaving or waxing. Folliculitis occurs when follicles become infected or irritated, leading to tender, red bumps. These lumps typically resolve once inflammation subsides or the ingrown hair is released.
Hidradenitis suppurativa is a chronic skin condition causing painful, boil-like lumps and abscesses, often in areas like the armpits where skin rubs. These may rupture, drain pus, and lead to scarring or tunnels. It involves blocked hair follicles and sweat glands.
Accessory breast tissue, a natural anatomical variation, can extend into the armpit. Benign breast lumps or hormonal changes from menstruation, pregnancy, or lactation can make this tissue noticeable or tender. It responds to hormonal fluctuations like regular breast tissue.
Potentially Serious Causes
Severe or persistent bacterial infections can cause armpit abscesses requiring medical intervention. These infections cause significant pain, redness, and swelling, and may not resolve without proper treatment.
Lymphoma, a lymphatic system cancer, can cause enlarged armpit lymph nodes. These cancerous nodes are often painless, firm, or rubbery, and can grow considerably. While affecting lymph nodes body-wide, the armpit is a common site.
Metastatic cancer, where cells spread from their original site, frequently affects lymph nodes. Breast cancer often spreads to armpit lymph nodes due to lymphatic drainage. An armpit lump may be the first sign of cancer originating elsewhere.
Leukemia, a blood cancer, can also cause swollen lymph nodes, including in the armpit, due to abnormal white blood cell accumulation. Persistent or unexplained lymph node swelling should always be investigated.
When to Seek Medical Attention
Seek medical attention for an armpit lump if certain characteristics or symptoms are present. Any lump that persists over two weeks, feels hard, grows, or is fixed in place warrants professional evaluation.
Associated symptoms indicating medical consultation include fever, night sweats, or unexplained weight loss, which can signal systemic issues. Skin changes over the lump, like redness, warmth, dimpling, or any discharge, also prompt a doctor’s visit.
Prompt evaluation is important if the lump appears suddenly without clear cause, or persists despite home care. Women should have any new armpit lump checked immediately due to its connection to breast health. Do not self-diagnose.
Understanding Diagnosis and Management
Diagnosis typically begins with a thorough medical history and physical examination. The doctor will ask about the lump’s onset, changes, and any symptoms. A physical exam assesses its size, texture, mobility, and tenderness.
Depending on initial findings, diagnostic tests may be ordered. Blood tests identify infection or systemic issues. Imaging studies like ultrasound, mammogram, or MRI provide detailed views; ultrasound is often first-line.
A biopsy may be performed for a definitive diagnosis, involving removal of a tissue sample or the entire lump for microscopic examination. Types include fine-needle aspiration (cells with thin needle), core needle biopsy (small tissue cylinder), or excisional biopsy (entire lump surgically removed).
Management depends on the underlying cause. Bacterial infections are typically treated with antibiotics. For benign conditions like lipomas or cysts, watchful waiting or surgical removal may be considered if they cause discomfort. Cancerous lumps require complex treatment, potentially involving surgery, radiation, chemotherapy, or other specialized therapies.