Armpit Lumps and Pain

Breast cancer typically presents with:

• A painless lump, dimpling, swelling or redness in a breast, usually only on one side
• Sometimes, the nipple tenderness or, rarely, retraction

The cancer can spread into the lymph nodes above the collar bone (supraclavicular nodes) and in the armpit (axillary nodes) on the same side.

Lymph nodes are pea-sized organs that filter the lymph, that is the fluid that flows through them via the lymph vessels. Normal lymph nodes are not tender and are too small to be detected by the fingers.

Lymph nodes with breast cancer metastases in them are usually painless, enlarged, hard, fixed (you cannot move them with the fingers) and without visible changes in the overlying skin.

Cancers other than breast cancer can spread into the armpit lymph nodes and present as painless hard lumps.

• Hodgkin lymphoma may present with painless lumps in the neck and one or both armpits; pain in the armpits and chest can be triggered by drinking even small amount of alcohol.
• Non-Hodgkin lymphoma
• Acute or chronic lymphocytic leukemia, a cancer of white blood cells, can present with enlarged lymph nodes in the neck, armpits and groin and enlarged spleen.
• Melanoma in an arm is a highly malignant skin cancer that appears as a black, brown or blue mole up to about 1 cm in size.
• Advanced lung cancer

A sebaceous cyst, which develops after a blockage of sebaceous gland, can present with a painless or tender lump with a small opening, through which a white, thick and greasy material can be squeezed. The overlying skin can be reddened.

Autoimmune diseases, such as rheumatoid arthritis or systematic lupus erythematosus (SLE), can present with painless lumps in the armpits on one or both sides.

Shingles--a reactivation of the Herpes zoster virus in a spinal nerve--can cause painless lymph node enlargement in the armpit, usually only on one side.

Inflammatory Breast Cancer

In a rare inflammatory breast cancer, both the original cancer in the breast and its metastases into the lymph nodes can be painful.

Infected Lymph Nodes

When the lymph nodes get infected, they can become enlarged and painful.

• Bacterial infections in the arm, such as a boil, cellulitis or cat scratch disease, can spread into an armpit and cause painful and enlarged lymph nodes.
• Infectious mononucleosis can present with enlarged and painful lymph nodes in the neck, armpits and groin, usually on both sides, sore throat and fever.
• Common viral infections, such as common cold and flu, can cause painful, but rarely enlarged, lymph nodes in the armpits.
• Toxoplasmosis, a parasitic infection caused by ingestion of the cat feces, can cause painful and enlarged lymph nodes in the armpits.
• Rat-bite fever (mainly in Asia) and bubonic plague (mainly in Africa) can cause fever and very painful lymph nodes in the armpits.

A local injury of the armpit due to a direct hit, carrying a heavy backpack or using underarm crutches, can result in armpit pain accompanied with bruising, which may persist for few weeks.

Local Infections and Armpit Pain

A bacterial infection of a hair follicle (staphylococcal folliculitis) can present with a single, but usually multiple small red and tender bumps with white centers. When several infected follicles join together, they can form a furuncle, which appears as a rough, tender pea-sized lump. The infection can heal on its own in few weeks.

Hidradenitis suppurativa is a chronic infection of the tissues under the skin in the armpit. It can present with underskin lumps, which may ooze fluid and scar over. Overweight women are at increased risk.

Fungal infections (ringworm or intertrigo) with reddened, scaly or cracked skin can occur in individuals with impaired immunity, for example, due to diabetes mellitus, HIV/AIDS, chemotherapy or treatment with steroids. Antifungal creams can help within few weeks.

Causes of Painful Armpit Rash

• Armpit shaving can result in ingrown hair with irritating red bumps.
• Allergic reaction to deodorants, soaps or perfumes can result in red itchy scaly rash or blisters.
• Sweat rash (prickly heat) can appear in women living in a hot environment as multiple itchy bumps in the armpits.
• Sweat retention due to blocked sweat glands, mainly in young females, can present with red itchy rash in the armpits, around the breast nipples and in the pubic area.

Muscle Strain

Repeated lifting of heavy objects with an extended arm or repeated sprints with excessive arm swinging can result in a strain of the serratus anterior muscle, which runs from the side of the chest to the shoulder blade on each side. Sharp pain on the side of the chest, in the armpit, below a shoulder blade and on the inner side of the arm is aggravated by deep breathing and lifting the arms forwards.

Cyclic Breast Pain

Some women experience pain in one or both breasts or armpits in the second part of the menstruation cycle -- between ovulation and menstruation.

Mastitis

Mastitis is an infection of a breast that usually occurs during breastfeeding. The affected breast and armpit on one or both sides is reddened, swollen and tender.

Thumbnail source: Nicolas Calderon, Flickr, CC licence