Lump on Neck, Groin or Armpit: Causes & Treatment

Updated in March 2022

A lump felt in the groin, neck or armpit may be a swollen lymph node, which can occur due to infection or local inflammation in the area. These lumps usually appear as one single lump or a group of them under the skin of the neck, head or groin. They may or may not be painful, and usually last between 3 and 30 days.

Lymph nodes are small structures part of the immune system that act as filters for substances or microorganisms. Their main job is to help to fight infections by attacking and destroying foreign invaders, which are then transported by lymphatic fluid.

Swollen lymph nodes, also called adenopathy, are usually a sign of mild and transient inflammation. When the lump persists for more than 1 month, grows more than 2 cm or there are several scattered around the body, it may be a sign of a more serious diseases such as cancer or autoimmune diseases. Learn more about swollen lymph nodes in other areas of the body.

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Main causes

The most common causes of swollen. lymph nodes in the neck, groin or armpit are:

1. Skin inflammation

Any local inflammation can result in a reactive lymph node. The node swells when it is working to filter out excess bacteria, fluid or other substances from the area. It is common for lymph nodes to become swollen due to chemical skin irritations (e.g. from deodorant, small wounds (e.g. after hair removal), folliculitis, or an ingrown hair.

Inflammation that occurs in the airways or oral region, such as allergic rhinitis, pharyngitis, gingivitis or a tooth inflammation, for example, can particularly cause enlarged lymph nodes in the neck.

2. Infections

Any type of infection can cause a swollen lymph node. Some of the most common infections are a cold, flu, otitis, sinusitis, pharyngitis or any type of virus such as Zika or dengue. These infections usually result in swollen lymph nodes in the neck, nape, jaw or behind the ear.

Other types of infection, such as pneumonia and bronchitis, can also cause swollen lymph nodes in the armpit, while abdominal or genital infections (like gastroenteritis, genital HPV, syphilis, candidiasis, or bacterial vaginosis) and leg or foot injuries can cause swollen lymph nodes in the groin.

3. Autoimmune diseases

Diseases that interfere with the immune system can cause swollen lymph nodes. Some examples are lupus, arthritis, vasculitis and inflammatory bowel disease. Learn more about the most common autoimmune diseases and their associated symptoms.

4. Cancer

Swollen lymph nodes caused by cancer is more rare. They usually appear scattered throughout the body and are hard when palpated. These lymph nodes usually do not disappear within 1 or 2 months and do not stop growing. Any type of cancer can cause swollen lymph nodes, but some cancers that are most prone to the development of this swelling are lymphoma, breast cancer and lung cancer. Learn about other sign and symptoms of cancer.

When to go to the doctor

A lump in the groin, neck or armpit can be concerning and indicate a more serious disease when:

  • It is located in the arms or around the clavicle;
  • It is spread throughout various parts of the body;
  • It measures more than 2,5 cm;
  • It is hard and does not move;
  • It doesn’t improve after 1 month;
  • It is accompanied by a fever that does not improve in 1 week, night sweats, weight loss or malaise.

If you experience any of these symptoms, you should see a doctor, who may order urgent bloodwork to assess for possible infection or inflammation in the body. If a diagnosis cannot be concluded from bloodwork, a biopsy of the lymph node may be requested, which will show if it has benign or malignant features.

How to treat swollen lymph nodes

To treat swollen lymph nodes, rest and hydration in advised. Ideally the cause of the reactive lymph node should be identified and treated, as a lymph node cannot be treated directly. When the underlying infection or inflammation is resolved, the swollen lymph node will disappear, as the body no longer needs to fight any foreign invaders.

Analgesics or anti-inflammatory drugs can relieve pain or sensitivity in the area. A good home remedy is to drink eucalyptus tea and use clay compresses as they help to decrease swelling and strengthen the body's defenses.