The armpit is a complex anatomical region containing a high concentration of sensitive structures, including muscle groups, blood vessels, nerves, and numerous lymph nodes. Pain in this area is a frequent complaint that often causes concern due to its proximity to the breast tissue and chest wall. While many instances of discomfort are temporary and harmless, the symptom can arise from a wide range of causes, from simple skin irritations to more complex medical conditions. Understanding the nature and duration of the pain, along with any accompanying symptoms, helps determine the need for professional medical evaluation.
Common and Transient Causes of Axillary Pain
The majority of axillary pain stems from straightforward issues that resolve quickly, often related to muscle use or superficial skin changes. Muscle strain is a common culprit, involving the pectoral or intercostal muscles, which can be overworked during activities like weightlifting or intense throwing motions. This pain is typically exacerbated by movement and usually subsides with rest, ice, and anti-inflammatory medication over several days.
Skin irritation is another frequent, transient source of pain, particularly in an area prone to friction, moisture, and hair removal. Conditions like folliculitis (inflammation of the hair follicles) or small nicks from shaving can introduce bacteria, leading to minor, temporary infections or boils. Contact dermatitis caused by ingredients in deodorants, antiperspirants, or laundry detergents can also cause redness, itching, and mild tenderness.
Temporary swelling of lymph nodes is a common benign cause. The armpit contains numerous nodes that routinely enlarge in response to a localized infection elsewhere in the body, such as a cold, flu, or a minor cut on the arm. When swollen due to a routine infection, these nodes are usually tender to the touch, mobile, and resolve once the underlying illness clears, typically within one to two weeks.
Chronic or Specific Skin and Nerve Conditions
Recurrent or chronic armpit pain associated with specific skin changes may point toward a defined medical condition requiring targeted intervention. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that frequently affects the axilla, presenting as painful, deep-seated nodules and abscesses. These lesions often recur and can develop into tunnels beneath the skin called sinus tracts, potentially resulting in significant scarring.
Pain involving burning, tingling, or numbness may indicate nerve irritation or entrapment. Damage to the axillary nerve, a branch of the brachial plexus, can cause pain and weakness in the shoulder region that radiates into the armpit. Intercostobrachial neuralgia involves the disruption of nerves running through the chest wall and armpit, sometimes occurring after chest or breast surgeries.
Infections like shingles, caused by the varicella-zoster virus, can present as intense, deep pain in the armpit several days before the characteristic blistering rash appears. Deep sebaceous or epidermoid cysts can also become inflamed or infected, leading to a painful, firm lump. Unlike transient causes, these conditions often require specific prescription medications, minor procedures, or long-term management strategies.
Urgent Symptoms Requiring Immediate Medical Attention
Symptoms associated with axillary pain that signal a more serious underlying condition should prompt a visit to a healthcare provider without delay. Any lump in the armpit that is fixed, hard, or rapidly increasing in size should be evaluated, especially if it persists for longer than two weeks. While most armpit lumps are benign, a non-tender, immobile lump that does not shrink is a key sign requiring professional assessment to rule out conditions like certain cancers or lymphoma.
Systemic symptoms are also significant warning signs, including unexplained fever, drenching night sweats, or significant, unintentional weight loss. When combined with persistent axillary pain or swelling, these non-specific symptoms suggest the body is fighting a systemic process that goes beyond a local irritation or minor infection.
Signs of a rapidly spreading or severe infection also warrant immediate medical care. These include pain accompanied by widespread redness, warmth, or red streaking extending away from the armpit, which can indicate cellulitis. Additionally, if the pain is sudden and severe, accompanied by swelling in the arm or hand, or occurs alongside chest pain, shortness of breath, or heart palpitations, seeking emergency care is necessary to exclude potential vascular issues or other life-threatening conditions.
The Medical Diagnostic Process
The medical evaluation for persistent or concerning axillary pain begins with a detailed history and a thorough physical examination. The healthcare provider will carefully palpate the axilla to assess the lymph nodes, noting their size, consistency, mobility, and any tenderness. A skin assessment is also performed to check for rashes, cysts, or signs of chronic inflammatory conditions like hidradenitis suppurativa.
If an infection is suspected, initial blood work, such as a complete blood count (CBC), may be ordered to check for elevated white blood cell counts. If a mass or persistent lymphadenopathy is identified, imaging is typically the next step. An ultrasound of the axilla is the most common initial imaging modality because it can effectively differentiate between a solid mass and a fluid-filled cyst, and characterize the internal structure of lymph nodes.
For a comprehensive evaluation, especially in patients with risk factors, an ultrasound is often complemented by a diagnostic mammography or digital breast tomosynthesis to evaluate for underlying breast lesions. If imaging reveals suspicious findings, such as a lump with irregular borders or an abnormal-looking lymph node, a definitive diagnosis requires a biopsy. This procedure involves obtaining a small tissue sample, usually via a needle, which is then analyzed by a pathologist to determine the exact cause of the pain or lump.