Pain in the armpit can originate from the shoulder. Understanding the potential sources of discomfort is important for proper evaluation. Pain referral patterns can be complex, as different body areas share nerve pathways.
Understanding the Connection
Pain originating in the shoulder can manifest in the armpit due to shared anatomical structures, primarily nerves and muscles. The brachial plexus, a network of nerves extending from the spinal cord in the neck through the shoulder and into the arm, plays a significant role. Irritation or compression of these nerves in the shoulder area can cause pain to radiate along their pathways into the armpit.
Muscles spanning the shoulder and armpit regions also contribute to referred pain. For instance, the pectoralis muscles in the chest and the latissimus dorsi in the back attach around the shoulder and can refer pain to the armpit when strained or injured. Inflamed connective tissues and bursae in the shoulder can also lead to discomfort in the armpit.
Specific Shoulder Conditions Causing Armpit Pain
Several shoulder conditions commonly lead to referred pain in the armpit. Rotator cuff injuries, such as tendinitis or tears, are common causes. The rotator cuff muscles (supraspinatus, infraspinatus, subscapularis, and teres minor) stabilize the shoulder joint. Inflammation or damage to their tendons can cause pain that spreads to the front of the chest near the armpit, often worsening with arm movement, especially when lifting overhead, and disturbing sleep.
Nerve impingement, such as thoracic outlet syndrome (TOS), can also cause armpit pain. TOS occurs when nerves or blood vessels between the collarbone and the first rib are compressed. This compression can lead to pain, numbness, or tingling in the shoulder, arm, and armpit, sometimes with weakness.
Muscle strains, particularly of the pectoralis major, can cause sudden pain in the front of the armpit, often during activities involving forceful contraction against resistance, such as weightlifting. Shoulder joint problems like arthritis, which involves cartilage breakdown, can also cause pain, including in the armpit. This pain may be felt deep within the joint and accompanied by stiffness and a reduced range of motion.
Other Causes of Armpit Discomfort
While shoulder issues can cause armpit pain, discomfort in this area can also arise from sources unrelated to the shoulder. Swollen lymph nodes are a common cause, often indicating the body is fighting an infection or inflammation. These nodes may feel like small, tender bumps and can swell due to viral infections like the flu, bacterial infections, or, less commonly, more serious conditions such as cancer.
Skin conditions specific to the armpit can also cause pain and discomfort. Examples include folliculitis, an infection of hair follicles, and hidradenitis suppurativa (HS), a chronic condition causing painful lumps, boils, and abscesses in areas where skin rubs together, including the armpits. These skin issues can lead to itching, burning, and pus-filled lesions. Muscle strains in the chest wall, unrelated to the shoulder, can also refer pain to the armpit. Nerve issues like intercostal neuralgia, which affects nerves below the ribs, can cause sharp, burning pain that sometimes radiates to the armpit or shoulder blade.
When to Seek Medical Attention
It is important to seek medical attention for armpit pain if it is severe, persistent, or worsens over time. Pain accompanied by numbness, tingling, or weakness in the arm or hand warrants professional evaluation. Swelling, redness, or warmth in the armpit area, especially if combined with fever, suggests an infection or inflammation that requires prompt medical assessment.
Any new or unexplained lumps in the armpit should also be examined by a healthcare provider. If armpit pain is associated with unexplained weight loss, night sweats, or difficulty breathing, medical consultation is advisable. A professional diagnosis is important for identifying the underlying cause of armpit pain and determining the appropriate course of treatment.