Armpit soreness, ranging from mild discomfort to significant pain, can stem from various factors. While some causes are easily addressed at home, others may require medical attention.
Common Causes of Armpit Soreness
Skin irritation is a common cause of armpit soreness. Shaving can lead to razor burn, characterized by redness, tenderness, and small bumps, or cause ingrown hairs when hair curls back into the skin, resulting in painful inflamed spots. Allergic reactions to ingredients in deodorants, antiperspirants, soaps, or laundry detergents can trigger contact dermatitis, causing itching, stinging, and a rash. Constant friction from tight clothing or excessive moisture can also irritate the delicate underarm skin, leading to chafing or heat rashes.
Bacterial infections frequently contribute to armpit pain. Folliculitis, an infection of hair follicles, appears as small, red, tender bumps, often developing after shaving. A boil, or furuncle, is a deeper infection of a hair follicle or oil gland, typically caused by Staphylococcus aureus bacteria, forming a painful, pus-filled lump that grows over several days. In some cases, recurring painful lumps in the armpit may indicate hidradenitis suppurativa, a chronic inflammatory skin condition affecting sweat glands and hair follicles, which can lead to abscesses and scarring.
Beyond skin issues, muscle strain can cause considerable armpit discomfort. The armpit area houses muscles like the pectoralis major and coracobrachialis, which can become strained from overuse, heavy lifting, or strenuous arm movements. This type of pain often presents as aching or sharp sensations, sometimes limiting arm movement. Furthermore, benign cysts, such as sebaceous cysts or epidermal inclusion cysts, can develop under the skin. These slow-growing, fluid or pus-filled lumps are usually harmless, but can become painful, red, and swollen if inflamed or infected.
The Role of Lymph Nodes in Armpit Pain
Axillary lymph nodes in the armpit are an important component of the body’s immune system. These small, bean-shaped structures, typically numbering 20 to 40, filter lymph fluid from the upper limbs, breasts, and upper trunk. Their primary role is trapping and neutralizing pathogens like bacteria, viruses, and other harmful substances before they spread into the bloodstream.
When the body fights infection or responds to localized injury or inflammation, these lymph nodes can swell. Common causes of this enlargement include bacterial or viral infections in the arm, hand, or breast, systemic infections like the flu or mononucleosis, and reactions to vaccinations. Swelling occurs as immune cells proliferate within the nodes to combat the threat.
This enlargement can lead to armpit pain. As the lymph nodes expand, they press against surrounding nerves, blood vessels, and tissues in the confined space of the armpit, causing tenderness, aching, or sharp discomfort. The pain signals the immune system is actively engaged in a localized response.
Accompanying Symptoms and When to Seek Medical Advice
Recognizing additional symptoms alongside armpit pain helps determine if medical attention is needed. Monitor for persistent or worsening pain that doesn’t improve with home care. New or growing lumps in the armpit warrant evaluation, especially if hard, fixed, or accompanied by skin changes.
Spreading redness or warmth around the area, coupled with increasing pain, can indicate an infection requiring treatment. Systemic symptoms like fever, chills, or unexplained weight loss, when present with armpit pain, suggest a more widespread issue.
Pus drainage from a lump or sore, or pain significantly limiting arm movement, should prompt a doctor’s visit. For women, associated breast changes, including lumps, dimpling, or nipple discharge, alongside armpit pain, necessitate prompt medical assessment.
General Care and Prevention Tips
Maintaining proper underarm hygiene is a simple yet effective way to prevent soreness. Regular washing with mild soap and thoroughly drying the skin helps reduce bacterial and fungal growth, which thrives in warm, moist environments. When shaving, use a clean, sharp razor with shaving cream to minimize irritation, razor burn, and the risk of ingrown hairs or cuts. Shaving at night allows the skin to recover before applying deodorant.
Choosing appropriate personal care products can prevent discomfort. If irritation is suspected, opt for hypoallergenic or fragrance-free deodorants and antiperspirants to reduce allergic reactions. Temporarily discontinuing product use can help identify the source of irritation.
Wearing loose-fitting clothing made from breathable fabrics, such as cotton, reduces friction and allows air circulation, preventing moisture buildup. For minor pain or localized inflammation, applying a warm compress can soothe the area and promote circulation. Over-the-counter pain relief medications, such as ibuprofen or acetaminophen, can manage discomfort.