Neck Swelling: Causes and When to Worry

What causes neck swelling

The neck contains more than 100 lymph nodes, the thyroid gland, two large salivary glands under the jaw (submandibular) and one in front of each ear (parotid), as well as muscles, blood vessels and the airway. Swelling can come from any of these. Where the swelling sits gives the first clue.

Common causes

Swollen lymph nodes from infection

This is the usual reason. Nodes swell when they filter germs from a cold, sore throat, tonsillitis, ear infection, dental infection or skin infection of the scalp. They feel soft or rubbery, tender and movable, usually less than 1 to 2 cm across. They shrink back within 2 to 3 weeks of the infection clearing. When a node itself becomes infected, it is called lymphadenitis and becomes very tender, red and warm.

Infectious mononucleosis (glandular fever)

Mononucleosis, caused by the Epstein-Barr virus, causes marked swelling of nodes on both sides of the neck, a severe sore throat, fever and exhaustion. It is most common in teenagers and young adults and can take 2 to 4 weeks to settle.

Dental infection

A tooth abscess can cause swelling of the jaw, cheek and upper neck, with a throbbing toothache and sometimes fever. Spreading dental infection is a common cause of serious deep neck infections.

Salivary gland problems

• Salivary stones block the submandibular duct, causing swelling under the jaw that appears with eating and then subsides.
• Sialoadenitis is a bacterial infection of the gland, causing a painful, red swelling and sometimes pus in the mouth. It is more common in older or dehydrated people.
• Mumps causes swelling of one or both parotid glands, giving a "hamster cheek" appearance, with fever.

Thyroid enlargement

A goiter is an enlarged thyroid at the front of the neck that moves up when you swallow. Causes include iodine deficiency, Hashimoto's thyroiditis, Graves' disease and multiple nodules. Most thyroid nodules are benign, but they are checked with ultrasound. Painful thyroid swelling after a viral illness suggests subacute thyroiditis.

Allergic swelling

Angioedema causes rapid swelling of the lips, face, tongue and throat. It can follow foods, insect stings or medicines such as ACE inhibitors. Throat swelling can block the airway and is an emergency.

Cysts

Branchial cleft cysts on the side of the neck and thyroglossal duct cysts in the midline are present from birth but often show up in children or young adults, sometimes after a cold makes them swell.

One-sided neck swelling in adults over 50

In adults over about 40 to 50, a new, painless, one-sided neck lump that persists for more than 3 weeks has a much higher chance of being cancer than in children. The most common cancers are:

• Head and neck squamous cell cancer spread to a lymph node, especially in smokers and heavy drinkers, or from HPV-related throat cancer in non-smokers
• Lymphoma, often with rubbery nodes, night sweats, fever or weight loss
• Thyroid cancer, presenting as a firm nodule
• Salivary gland tumors, usually in the parotid in front of the ear

The American Academy of Otolaryngology advises that adults with a neck mass lasting more than 2 weeks without a clear infection, or with high-risk features, should be evaluated, and should not be repeatedly given antibiotics without follow-up.

When to worry about neck swelling

See a doctor promptly if the swelling:

• has lasted more than 3 weeks
• is hard, fixed in place, or keeps growing
• is larger than about 2 cm (3/4 inch)
• comes with hoarseness, trouble swallowing, ear pain on one side or a mouth ulcer that will not heal
• comes with night sweats, fevers or unexplained weight loss
• sits just above the collarbone

How neck swelling is diagnosed

1. History: how long it has been there, recent infections, dental problems, smoking, alcohol, weight loss and travel.
2. Examination: of the neck, mouth, throat, ears, scalp and skin, and of other lymph node areas.
3. Ultrasound: the first-choice scan. It shows whether the lump is a node, cyst, thyroid or salivary gland and whether it looks suspicious.
4. Blood tests: full blood count, inflammatory markers, a mono test and thyroid function.
5. Fine-needle aspiration: a thin needle samples cells, often with ultrasound guidance.
6. CT or MRI: to see deeper structures or stage a cancer. A camera exam of the throat (nasendoscopy) looks for a primary throat cancer.

Neck swelling treatment

Treatment targets the cause:

• Viral infections: rest, fluids and acetaminophen (paracetamol) or ibuprofen at the label dose. The swelling goes down as you recover. Do not give aspirin to children or teenagers.
• Bacterial infections: antibiotics for strep throat, infected nodes or salivary gland infection. An abscess needs drainage.
• Dental infection: dental treatment such as drainage, root canal or extraction, plus antibiotics if infection is spreading.
• Salivary stones: hydration, sour candies to increase saliva flow, gland massage, and stone removal if they keep recurring.
• Thyroid problems: thyroid hormone, antithyroid medicine, radioactive iodine or surgery, depending on the cause and size.
• Angioedema: antihistamines and steroids for allergic swelling. Epinephrine for anaphylaxis.
• Cysts: surgical removal, usually after any infection has settled.
• Cancer: surgery, radiotherapy and chemotherapy, planned by a head and neck team.

Frequently asked questions

What causes one side of the neck to swell?

One-sided neck swelling is usually a lymph node responding to an infection on the same side, such as a sore throat, tooth or ear infection. Salivary gland problems and cysts are also common. In adults over 40, a painless one-sided lump lasting more than 3 weeks should be checked for cancer.

How long does neck swelling last?

Swollen glands from a cold or sore throat usually go down within 2 to 3 weeks. Mononucleosis can take up to a month. Swelling that persists beyond 3 weeks without a clear cause needs medical assessment.

What is the treatment for neck swelling?

It depends on the cause. Viral infections need rest, fluids and pain relief. Bacterial infections need antibiotics, and abscesses need drainage. Thyroid swelling may need medication or surgery. Allergic swelling is treated with antihistamines, steroids or epinephrine.

Is excessive neck swelling an emergency?

It can be. Rapid swelling, or any neck swelling with difficulty breathing, drooling, noisy breathing or trouble swallowing, can block the airway. Call 911 or your local emergency number straight away.

Can stress cause neck swelling?

Stress does not directly cause the neck to swell, but it can tighten neck muscles and make you more aware of normal lymph nodes. A visible or growing swelling has a physical cause and should be checked if it lasts.

Can a swollen neck be from the thyroid?

Yes. A thyroid swelling sits low at the front of the neck and moves up when you swallow. It may be a goiter or a nodule. Thyroid blood tests and an ultrasound identify the cause.