An armpit lump is swelling of one or more lymph nodes under the arm.
Lump in the armpit; Localized lymphadenopathy - armpit; Axillary lymphadenopathy; Axillary lymph enlargement; Lymph nodes enlargement - axillary; Axillary abscess
An armpit lump in a woman should be checked by a health care provider immediately, as it may be a sign of breast cancer.
Lumps in the armpit may have many causes. Lymph nodes are filters that can catch germs or cancerous tumor cells. When they do, lymph nodes increase in size and are easily felt.
Cysts and infections of the skin of the armpit may be caused by shaving or use of antiperspirants (not deodorants). This is most often seen in teens just beginning to shave.
Abscesses under the skin may also produce large, painful lumps in the armpit.
Other causes of armpit lumps may include:
Arm or breast infection
Cat scratch disease
Cancers such as lymphoma or breast cancer
Lipomas (harmless fatty growths)
Normal breast tissue (breast tissue extends into the armpit area)
Use of certain medicines or vaccinations
Shingles (herpes zoster)
Home care depends on the reason for the lump. Check with your health care provider to determine the cause.
Call your health care provider if
Call your doctor or nurse if you have any unexplained armpit lumps. Do not try to diagnose lumps without professional help.
What to expect at your health care provider's office
Your doctor or nurse will examine you and ask questions about your medical history and symptom, such as:
When did you first notice the lump?
Is it getting better, worse, or staying the same?
Are you breastfeeding?
Have you noticed any factors that make it worse?
What other symptoms are also present?
Is the lump painful?
The physical examination may include gently pressing the nodes with the fingertips.
Testing depends on what is found during the physical examination.
Armitage JO. Approach to the patient with lymphadenopathy and splenomegaly. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 171.
Tower RL II, Camitta BM. Lymphadenopathy. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 484.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.