Of all the places on your body, you would not expect your armpit to cause you so much pain. In fact, it is a sensitive place in the body. A great deal of nerves and blood vessels run through this area, and of course, it is close to the breast which can lead you to think of breast cancer. Fortunately, most pain in the armpit is harmless and doesn't need attention from a doctor. In certain circumstances, though, pain in the armpit may mean something significant.

You can have pain in your armpit in a number of ways. First, you could develop a lump under your arm, and it is the primary source of the pain. Sometimes the skin of the armpit can become irritated, and this can lead to a feeling of pain under your arm. Finally, the structures within your armpit can cause you pain - or the pain can radiate to that point from another place - and this can mean a totally different causative factor is at work. If you want to figure out what is causing your armpit pain, you have to consider a few different conditions.

Common Causes of Armpit Pain

Pain can occur under your arm for a number of reasons. One of the most common reasons is a brachial plexus injury. This is trauma that occurs when the shoulder is pressed down and the head is pulled away from that shoulder. It often occurs in contact sports or from a fall. In addition, problems with the nerves of the arm, or brachial plexus, such as neuropathy or dysfunction, can cause pain under the armpit.

Certain infections can cause pain under the arm, as well. Lymphangitis is caused by an acute streptococcal infection of the skin that infects the lymph node ducts, and many of these ducts exist under the arm. This can cause pain and red streaks from the site of the infection. Usually, antibiotics can clear this condition away. Other infections, such as skin abscesses, can cause lumps to form under the arm that are painful. Hair follicles can become infected and a large lesion can develop. Sometimes these abscesses require drainage and an antibiotic.

Lumps under the armpit are often painful, and they have several causes. Cancer, such as Hodgkin's lymphoma and metastasized breast cancer, can cause a painful lump to form in the armpit. Most lumps under the arm are harmless, however. They consist of blocked cysts, fatty growths, and excess breast tissue. Certain infections, such as chickenpox and infectious mononucleosis, can cause a painful lump under the arm, and they must run their course.

When to See Your Doctor

If you have persistent pain under your arm, you should likely see your doctor. If you have a lump of some kind, it may need to be opened up or the doctor should investigate it for possible cancerous processes. You may need an antibiotic or a biopsy of the mass to handle either condition.

One of the most important reasons not to ignore armpit pain is that sometimes the pain of a heart attack can be referred to the region. Most people are aware that a heart attack causes pain down the left arm, but for some people, a heart attack could present as pressure under the arm, especially the left. If your armpit pain is accompanied by chest pain, arm tingles, nausea, vomiting, or fatigue, you should be immediately evaluated by a doctor. In women, the signs of a heart attack are often atypical, which means that they are not the classic crushing chest pain. Sometimes in rare circumstances, the only outward sign of a heart attack may be an uncomfortable feeling under the arm. If you have any of the other symptoms or just don't feel right, you should seek medical advice.