An armpit lump refers to the enlargement of at least one of the lymph nodes under your arm. Lymph nodes are small, oval-shaped glands that are located throughout the body and play an important role in the immune system.
The lump may feel small, or be extremely visible in other cases. Armpit lumps may be caused by cysts, infection, or irritation due to shaving or using antiperspirants. However, these lumps may also indicate a serious health condition.
Seek medical attention if you have an armpit lump that gradually becomes enlarged, is not painful, or does not go away.
Most lumps are harmless and are usually the result of abnormal tissue growth. However, armpit lumps can be related to a more serious underlying health problem. Any unusual lumps should be evaluated by a doctor.
The most common causes of armpit lumps are:
- bacterial infections
- harmless fat tissue growths (lipomas)
- allergic reactions
- adverse reactions to vaccinations
- viral infections
- noncancerous fibrous tissue growth (fibroadenoma)
- breast cancer
- cancer of the lymphatic system (lymphoma)
- blood cancer in the bone marrow (leukemia)
Armpit lumps can occur in men and women of all ages. However, finding an armpit lump is most alarming for women because it may indicate breast cancer. Women should perform monthly breast exams and report any lumps to a doctor right away.
Note that breasts undergo hormonal changes during the menstrual cycle, and may tend to feel more tender or lumpy during this time. This is completely normal. For the most accurate results, perform breast self-exams about one week after your period starts.
A thorough physical examination is the first step in diagnosing an armpit lump. Your doctor will ask you questions about any changes in the lump, as well any pain you are experiencing in the area. Palpation, or massage, is used to determine the consistency and texture of the lump. This method is done exclusively by hand, as the doctor works to gently examine the lymph nodes.
In some cases, a physical exam may prove that the lump isn’t harmful. For example, people with benign lumps, such as a lipoma, don’t require additional treatment. If a lump is bothersome, however, a doctor can recommend treatment options to remove it.
Based on the results of your physical examination, your doctor may order further testing to rule out infection, allergic reaction, or cancerous changes. Your doctor may order a combination of diagnostic tests, including:
- complete blood count to measure the number of red and white blood cells in your system
- chest or breast X-ray (mammogram): an imaging test that will allow your doctor to better see the lump
- biopsy (removing a small piece of tissue from the lump for testing)
- allergy testing
The course of treatment your doctor recommends will depend on the underlying cause of the lump. Bacterial infections can be treated with oral antibiotics. After several days, the armpit lump should start to disappear as your body fights the infection. If your lump is associated with allergies, it should subside once you start medication and learn to avoid your allergy triggers.
In most cases, armpit lumps will not require any treatment. Home remedies such as warm compresses and over-the-counter pain relievers may be used to ease any discomfort. Lumps that don’t require treatment include those associated with:
- viral infections
- fibroadenoma (noncancerous breast lumps)
If your armpit lumps are found to be cancerous, your doctor may refer you to a specialist for further care. Treatment will depend on the type of cancer and what stage you are in, and it may involve a combination of:
- radiation therapy
The outlook for an armpit lump depends on its cause. For example, a lump that stems from a viral infection will eventually go away on its own. However, a lipoma, while harmless, is permanent.
The outlook for an armpit lump caused by cancer will depend on a variety of factors, including the stage of cancer and whether the tumors have spread to other parts of the body. For the best chance of recovery, it’s important to obtain a timely diagnosis. Even if you don’t think the lump is harmful, it’s best to contact your doctor for an accurate diagnosis.