Most neck lumps are swollen lymph nodes reacting to a common infection like a cold or sore throat. They’re the single most frequent cause of a new lump in the neck, and they typically shrink on their own within two weeks. But infections aren’t the only explanation. Thyroid nodules, cysts, salivary gland problems, and soft tissue growths can all produce a noticeable lump, and in a small percentage of cases, a neck mass turns out to be cancerous.
Swollen Lymph Nodes From Infection
Your neck contains dozens of lymph nodes, small filtering stations that trap viruses and bacteria. When your immune system ramps up to fight an infection, nearby lymph nodes swell with white blood cells. This is called reactive lymphadenopathy, and it’s by far the most common reason people notice a lump in their neck. The nodes usually feel tender, slightly rubbery, and movable under the skin. They often appear on one or both sides of the neck, just below the jawline or along the front of the muscle that runs from your ear to your collarbone.
Common viral triggers include cold and flu viruses, respiratory syncytial virus, adenovirus, and the viruses that cause mono (Epstein-Barr) and similar illnesses (cytomegalovirus). Bacterial infections, particularly staph and strep, can also cause nodes to swell and sometimes fill with pus, creating a more painful, rapidly enlarging lump. In children, a viral upper respiratory infection is the most frequent cause of swollen neck nodes. These infection-related lumps generally peak in size over a few days, then gradually return to normal as the illness resolves.
Thyroid Nodules
The thyroid gland sits at the base of your neck, just below the Adam’s apple. Lumps that form within the thyroid are extremely common, especially in women and people over 40. Most thyroid nodules are benign fluid-filled cysts or overgrowths of normal thyroid tissue. You might feel a firm, round lump in the center or slightly off to one side of the lower neck that moves up and down when you swallow.
A small number of thyroid nodules are cancerous. Early thyroid cancer rarely causes symptoms. As it grows, you may notice hoarseness, a feeling that shirt collars are getting tighter, difficulty swallowing, or swollen lymph nodes nearby. A lump in the lower front of the neck that doesn’t go away warrants an ultrasound and, if the nodule looks suspicious, a needle biopsy to check for cancer cells.
Salivary Gland Problems
A lump near the angle of the jaw or under the chin may involve a salivary gland. The most distinctive cause is a salivary stone, a hardened mineral deposit that blocks the duct draining saliva from the gland. Nearly all salivary stones form in the submandibular gland, located just below the back corner of the jawbone.
The hallmark symptom is pain and swelling that flares during meals. When you start eating, the gland produces saliva that can’t drain past the stone, so the area swells and hurts. The discomfort typically lasts an hour or two and then fades until the next meal. You might also notice a bitter taste, a painful lump under the tongue, or difficulty opening your mouth wide. Salivary glands can also develop benign or malignant tumors, which tend to present as a slow-growing, painless lump near the ear or under the jaw.
Cysts and Soft Tissue Growths
Not every neck lump involves a lymph node or gland. Several types of benign growths can appear just beneath the skin.
Lipomas are slow-growing collections of fat cells. They feel soft, doughy, and rubbery, and they slide easily under your fingers when you press on them. They’re painless and harmless, though they can grow large enough to be cosmetically bothersome.
Epidermoid cysts (sometimes called sebaceous cysts) form when skin cells get trapped beneath the surface and create a sac filled with a thick, cheese-like material. They feel firmer than lipomas, are often anchored closer to the skin rather than sliding freely, and sometimes have a small dark opening (a pore) visible on the surface. They can become red, swollen, and painful if they get infected.
Two types of congenital cysts can also show up in the neck, most commonly in children and young adults. Thyroglossal duct cysts appear in the midline of the neck, typically between the Adam’s apple and the chin, and move upward when you stick out your tongue. Branchial cleft cysts appear along the side of the neck. Both are present from birth but may not become noticeable until they enlarge or get infected.
How Malignancy Risk Changes With Age
In a study of over 4,100 adults with neck masses, 5% were found to be malignant. That rate wasn’t evenly distributed across age groups. For patients younger than 40, the malignancy rate was about 2%. For those 70 and older, it rose to roughly 8%. In children, cancerous neck masses are uncommon, and the vast majority of lumps are reactive lymph nodes from infection.
Cancers that cause neck lumps include lymphoma, thyroid cancer, and metastatic squamous cell carcinomas that originate in the mouth, throat, or voice box. Head and neck cancers are strongly linked to tobacco use, heavy alcohol consumption, and infection with certain strains of human papillomavirus (HPV).
Features That Raise Concern
Certain characteristics of a neck lump suggest it needs prompt evaluation. According to guidelines from the American Academy of Otolaryngology, physical exam features that increase the suspicion of malignancy include a mass that is firm or hard to the touch, fixed to surrounding tissue rather than freely movable, larger than about 1.5 centimeters (roughly the width of a nickel), or accompanied by ulceration of the overlying skin.
A painless lump that has been present for more than two weeks without shrinking is also considered more suspicious than a tender, rapidly appearing node. Accompanying symptoms that warrant attention include persistent hoarseness, a sore throat that doesn’t resolve, difficulty swallowing, unexplained ear pain, a non-healing sore in the mouth, numbness in the face, or unexplained weight loss. Any combination of these with a neck lump should be evaluated rather than watched.
What Happens During Evaluation
If you see a doctor about a neck lump, the visit typically starts with a detailed history: how long the lump has been there, whether it’s growing, whether it’s painful, and whether you have other symptoms like fever, night sweats, or weight loss. The physical exam focuses on the lump’s size, texture, and mobility, as well as a careful look inside the mouth and throat.
For lumps that seem infection-related and have been present for less than two weeks, a short period of observation is often reasonable. The lump is expected to shrink as the infection clears. If it persists beyond two weeks, imaging is the next step. Ultrasound is commonly used for thyroid nodules and superficial lumps, while CT or MRI with contrast is preferred when malignancy is a concern. If imaging reveals a suspicious mass, a fine-needle aspiration biopsy can sample cells from the lump without surgery. For cystic masses that look potentially cancerous, evaluation continues until a firm diagnosis is reached, even if early results are inconclusive.