Lymphadenitis

Lymphadenitis vs lymphadenopathy

• Lymphadenopathy means any enlarged lymph node, from any cause, including infection, inflammation or cancer. See lymphadenopathy.
• Lymphadenitis means the node itself is inflamed, usually from infection, so it is tender and may be red and warm.

Causes

Viral

Colds, flu, COVID-19, infectious mononucleosis, adenovirus and HIV often cause several mildly tender nodes, especially in the neck.

Bacterial

• Strep and staph infections: a single, tender, rapidly enlarging node, often in young children or after strep throat, skin infection or impetigo
• Dental infections causing nodes under the jaw. See dental abscess
• Cat scratch disease: a tender node near a cat scratch or bite, often in the armpit or neck, lasting weeks
• Nontuberculous mycobacteria: a slowly growing, painless node that turns purple in a toddler
• Tuberculosis: firm, matted neck nodes, sometimes draining
• Sexually transmitted infections: groin nodes with syphilis, chancroid, lymphogranuloma venereum or genital herpes

Other causes

• Kawasaki disease in young children
• toxoplasmosis
• fungal infections
• rarely, inflammatory conditions such as Kikuchi disease or lupus

Symptoms

• a swollen, tender lump in the neck, armpit or groin
• red, warm skin over the node
• fever, tiredness
• symptoms of the original infection, such as sore throat, earache or a skin wound
• softening of the node if pus collects (abscess)

Diagnosis

A doctor examines the node's size, tenderness, texture and mobility and looks for a source of infection in the area it drains. Tests may include:

• strep test or throat swab
• blood count, inflammatory markers, and tests for mono, cat scratch disease or toxoplasmosis
• ultrasound to see whether the node contains pus
• tuberculosis testing if suspected
• needle aspiration or biopsy for nodes that do not improve, are hard or fixed, or have worrying features, to rule out lymphoma and other cancers

Treatment

• Viral lymphadenitis: no specific treatment; it settles as the infection clears.
• Bacterial lymphadenitis: antibiotics targeting strep and staph, typically for 10 days. Improvement is expected within 2 to 3 days.
• Abscess: drainage with a needle or a small incision.
• Cat scratch disease: often resolves on its own; antibiotics such as azithromycin for some.
• Nontuberculous mycobacteria: surgical removal of the node is often the most effective treatment.
• Tuberculosis: several months of anti-TB medicines.

Home care

• warm compresses for comfort
• acetaminophen (paracetamol) or ibuprofen for pain and fever, following the label dose; no aspirin for children or teenagers
• rest and fluids

Outlook

Most lymphadenitis resolves completely with treatment of the infection. The node may take several weeks to shrink back to normal size even after symptoms improve. Nodes that persist or have worrying features need further investigation.

Frequently asked questions

What causes lymphadenitis?

It is usually caused by infection, either in the node itself or in the area it drains. Common causes are viral infections, strep and staph bacteria, dental infections, skin infections, cat scratch disease and, less commonly, tuberculosis.

How long does lymphadenitis last?

Pain and redness usually improve within a few days of treatment, but the node may stay enlarged for 2 to 6 weeks. A node that is not shrinking after 4 to 6 weeks, or that keeps growing, should be checked again.

Is lymphadenitis serious?

Usually not. Most cases resolve with treatment of the infection. It can become serious if an abscess forms, if infection spreads to deep neck tissues, or if the swelling is actually caused by another condition such as lymphoma.

When should I worry about a swollen lymph node?

See a doctor if a node is larger than 2 cm, hard, painless or fixed, lasts more than 4 to 6 weeks, is above the collarbone, or comes with night sweats, weight loss or ongoing fever. Get urgent care for breathing or swallowing difficulty.