Swollen lymph nodes: what they mean 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 or mouth 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

In the neck or under the jaw: most often a cold, a throat, ear or tooth infection.

In the armpit: can come from a cut or infection on the arm or hand, among other causes.

In the groin: can come from a cut or infection on the leg or foot, or from a sexually transmitted infection.

According to MedlinePlus, nodes that appear suddenly and are painful are usually due to an injury or infection. Slow, painless swelling needs to be evaluated, because it can be due to a tumor.

A painful node is usually a sign your body is fighting an infection; the soreness often goes away in a couple of days, but the node can take several weeks to return to its normal size. According to MedlinePlus, see a doctor if:

• The nodes don’t get smaller after several weeks, or keep getting bigger
• They are red and tender
• They feel hard, irregular or fixed in place
• 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)

You see Dr. Diana Nieves Castro, a Puerto Rico-licensed general practice physician with several years of emergency-department experience, in English or Spanish. She asks when the swelling started, whether it came on suddenly, whether it hurts to touch, whether it has grown and what other symptoms you have. On camera she guides you to feel the node and show it to her.

We evaluate, diagnose and treat the infection that is usually behind it. If needed, we give you a lab order for a lab near you: for example a blood count, a mono test, and HIV or other STI tests with your consent. If appropriate, the doctor prescribes and we send your prescription to your pharmacy.

A video visit cannot rule out something serious in a lymph node. If the doctor thinks you need an in-person exam, imaging (such as an ultrasound) or a biopsy, we refer you. An online doctor visit costs US$79, the same price for every age. If the patient is under 21, a parent or legal guardian stays on camera for the whole visit and shows ID.

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