Lymph Node Under the Arm: Causes of Inflammation and Enlargement

You have felt a small lump in your armpit, and it hurts when pressed. Most often this is how a lymph node reacts to an ordinary infection. Below — what it may mean and when a doctor is needed.

Axillary lymph nodes: where they are and what they do

Lymph nodes are found throughout the body. They are part of the immune system: they help recognize and fight off infections.

The body has about 600 lymph nodes. Normally, only the submandibular, axillary, and inguinal ones can be felt.

The normal size is up to 1 cm in diameter. In a child, a node is considered enlarged if it is larger than 1 cm. For the elbow node the threshold is lower — 0.5 cm, for the inguinal node higher — 1.5 cm.

Why a lymph node under the arm becomes inflamed

The most common cause is infection. The node enlarges near the source to help the body cope with it. Most often the culprits are a cold, tonsillitis, otitis, or a skin infection.

• Infections: ARVI and influenza, tonsillitis, otitis, gum inflammation, tuberculosis, sexually transmitted infections.
• Immune and autoimmune diseases: HIV, rheumatoid arthritis.
• Tumors: leukemia, Hodgkin lymphoma, non-Hodgkin lymphomas. This is a rare cause.
• Medications: for example, phenytoin; there can be a reaction to the typhoid vaccine.

Axillary lymphadenitis: signs

Doctors call enlargement of lymph nodes lymphadenopathy. Lymphadenitis is inflammation of a node. Most often it affects the axillary and inguinal nodes.

The node feels like a painful lump under the skin. Sometimes only one node on one side is enlarged.

There may also be other symptoms: sore throat, cough, high fever. With a general body reaction — night sweats, weight loss, prolonged fever.

The node may remain enlarged for several weeks after the pain has gone.

Why a lymph node under the arm hurts

The node grows quickly — the capsule stretches, and pain appears. A node also hurts when there is inflammation with suppuration. Rarely, pain occurs with hemorrhage into the necrotic center of the node in malignant involvement.

Pain by itself does not distinguish a benign cause from a malignant one. Its absence also says nothing.

Painful nodes more often mean that the body is fighting an infection. The discomfort usually resolves within a couple of days. The size returns to normal more slowly — sometimes several weeks.

How a doctor determines the cause of node enlargement

First — examination and questions. When the enlargement appeared, suddenly or gradually, whether it hurts when pressed.

The doctor palpates all groups of nodes: submandibular, cervical, supraclavicular, axillary, inguinal. Notes the size, tenderness, consistency, adherence of nodes to each other, and location. On initial examination, only 17% of cases of generalized lymphadenopathy are found, so other areas are also checked.

Consistency suggests a great deal. A stony-hard node is typical of cancer metastasis. A firm elastic one is suspicious for lymphoma. A soft one is more often seen with infection.

Sudden painful enlargement is usually associated with trauma or infection. Slow and painless — a reason to rule out a tumor.

Tests may include blood tests, including a complete blood count with a leukocyte differential and liver function tests. Node biopsy, chest X-ray, and CT of the chest and abdomen are used.

When an enlarged axillary lymph node requires a doctor's examination

After an infection, the node usually shrinks within 1–2 weeks. If it grows or does not subside for longer than a week — a doctor is needed.

Reasons to come for an appointment: the node is hard, does not move when pressed, night sweats, very high fever. And if nothing bothers you except the node.

Other reasons: the node does not shrink for several weeks, turns red and hurts, seems lumpy or adherent to tissues. Plus fever, night sweats, unexplained weight loss. In a child — any node larger than 1 cm.

A node above or below the collarbone is a separate reason for examination, even without other symptoms.

An enlarged lymph node under the arm by itself is not a reason to call an ambulance. 103/112 — if severe difficulty breathing or marked difficulty swallowing is added.

This article is for reference. It does not replace a doctor's consultation, especially if the node does not go away.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer