Armpit lump

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Female breast

Lymphatic system

Swollen lymph nodes under arm

An armpit lump refers to enlargement of one or more lymph nodes in the armpit.

Lump in the armpit; Localized lymphadenopathy - armpit; Axillary lymphadenopathy; Axillary lymphs enlarged; Lymph nodes enlarged-axillary; Axillary abscess

Lumps in the armpit have various causes. Cysts and infections on the surface of the skin of the armpit may be caused by shaving or use of antiperspirants (as opposed to deodorants). This occurs most frequently in adolescents just beginning to shave. Abscesses under the skin may also produce large, painful lumps in the armpit.

Lumps may be produced by lymph nodes enlarged due to bacterial infections, viral infections, vaccinations, and malignancy. A breast self-examination should always include the armpit because breast cancer can enlarge the armpit lymph nodes even when the breast itself seems perfectly normal.

Lymph nodes are filters that can catch malignant tumor cells or infectious organisms. When they do, lymph nodes increase in size and are easily felt.

• Bacterial
  • Localized infection, possibly somewhere in the arm or breast draining into the glands of the armpit, or infection within the armpit itself
  • Cat scratch disease
  • Ascending lymphangitis
  • Lymphadenitis
• Viral
  • Infectious mononucleosis
  • Chickenpox
  • Shingles (herpes zoster)
  • HIV disease (AIDS)
• Malignant
  • Hodgkin's lymphoma
  • Non-Hodgkin's lymphoma
  • Leukemia
• Fungal
  • Sporotrichosis
• Antigenic
  • Smallpox vaccination
  • Typhoid vaccine
  • Measles, mumps, rubella vaccine (rare)
  • Allergic reaction possibly caused by sulfa drugs, iodine, or penicillin
• Other
  • Lipomas (harmless fatty growths)
  • Benign (harmless) cyst
  • Normal breast tissue (breast tissue extends into the armpit area)

Review Date: 11/02/2005
Reviewed By: Kenneth Wener, M.D., Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA. Review provided by VeriMed Healthcare Network.