Swollen lymph nodes: causes in the neck, armpit and groin, and when to see a doctor

Lymph nodes are part of your immune system: they help your body recognize and fight germs and infections. They are throughout the body, and you can feel them in the neck, under the jaw and chin, behind the ears, at the back of the head, in the armpits and in the groin.

When one or more get bigger, people call them "swollen glands" (the medical name is lymphadenopathy). Which nodes swell depends on the cause and the body part involved: a throat infection swells the ones in the neck, and a cut on the leg, the ones in the groin.

According to MedlinePlus, infections are the most common cause, for example:

• Colds, flu and other respiratory infections
• Throat or tonsil infections: see sore throat
• Mononucleosis: see mono
• An abscessed tooth, swollen gums, mouth sores or cold sores: see toothache
• Ear infections
• Skin infections: see skin infection
• Sexually transmitted infections (nodes in the groin)
• Less often: tuberculosis, HIV, rheumatoid arthritis, some medicines, and some cancers such as lymphoma or leukemia

According to the UK National Health Service (NHS), swollen glands feel like tender, painful lumps under the skin in the neck, armpit or groin. They can be on one side of the body or both.

Normally you don’t notice them. If you suddenly feel one or more lumps in your neck, behind your ears, in your armpit or in your groin, notice whether they hurt, whether they move when you push them, and whether you have other symptoms such as a sore throat, fever or a nearby cut. That is the first thing the doctor asks.

These are the most common. In the neck, under the jaw or "in the throat", they almost always come from a cold, a throat or tonsil infection, mono, an ear infection or an abscessed tooth. That is why your neck glands hurt when your throat is sore: they are filtering the infection.

Nodes on the head: behind the ears or at the back of the head. They can come from an ear or scalp infection. According to MedlinePlus, nodes that appear suddenly and are painful are usually due to an injury or infection. A lump in the neck that grows slowly and does not hurt needs to be evaluated, because it can be due to a tumor.

A painful swollen node in the armpit usually comes from a cut, a scratch or a skin infection on the arm, hand or chest on the same side. It can also swell with a body-wide infection such as a bad cold or mono.

Other causes of a lump in the armpit:

• A cat scratch or bite on the hand or arm: according to MedlinePlus, cat scratch disease swells the lymph nodes near the scratch.
• A [boil](route:condition-boils): not a lymph node, but a red, painful, pus-filled lump in the skin. According to MedlinePlus, the armpit is one of the places boils appear most.
• Some medicines and vaccines: MedlinePlus lists seizure medicines such as phenytoin, and the typhoid vaccine.

A lump in the armpit that doesn’t hurt, doesn’t go down or feels hard needs to be evaluated: the CDC lists a new lump in the breast or underarm among the warning signs of breast cancer. The doctor also asks about breast changes and, if you need an in-person exam, an ultrasound or a mammogram, we refer you.

See a doctor soon if the armpit node keeps growing, hasn’t gone down in 1 to 2 weeks, feels hard or fixed, or comes with fever, night sweats or weight loss. Go to the ER if it is red, hot and very painful with fever, or the redness is spreading quickly across the arm or chest.

In the groin, a swollen node can come from a cut or infection on the leg or foot (including an infected athlete’s foot or ingrown toenail), or from a sexually transmitted infection such as genital herpes or syphilis.

If you have sores, discharge or burning when you pee along with the node, the doctor orders STI tests with your consent. A bulge in the groin that gets bigger when you cough or strain, and is not a node, can be a hernia: the doctor tells you whether it needs to be seen in person.

A painful node is usually a sign your body is fighting an infection. According to the NHS, swollen glands usually go down on their own within 1 to 2 weeks. According to MedlinePlus and the NHS, see a doctor if:

• They haven’t gone down within 1 to 2 weeks, or keep getting bigger
• A swollen node just above or below the collarbone
• Swollen nodes with no other sign of illness
• They are red and tender
• They feel hard, irregular or fixed in place (they don’t move when you push them)
• You have fever, night sweats or unexplained weight loss: see night sweats and unexplained weight loss
• In a child, any node larger than 1 centimeter (0.4 inch)

A node that is hard, fixed and has not gone down in more than 2 weeks, or a node with night sweats, a fever that won’t go away or weight loss, needs an in-person exam and tests to find the cause. By video, the doctor evaluates you, gives you a lab order and refers you for the exam, imaging or biopsy you need. Don’t wait for it to go down on its own.

Video doctor visits 24/7: book online and choose your time right away.

According to MedlinePlus, an infected lymph node (lymphadenitis) can spread within hours. Go to the ER, or call 911 if it is severe, if you have:

• A red, hot, painful node with fever, or redness spreading quickly across the skin
• Swelling in the neck with trouble breathing or swallowing, or drooling
• High fever with feeling very ill or confused