When a lump appears beneath the jaw, it often causes concern, but the vast majority of these masses are benign and tied to common, easily treatable conditions. This area, known as the submandibular region, contains structures like lymph nodes and salivary glands that are prone to temporary swelling. Understanding the lump’s characteristics—whether it is soft or firm, painful or painless—is the first step in determining its source and the need for medical attention.
The Most Common Cause: Swollen Lymph Nodes
The most frequent reason for a lump under the jaw is lymphadenopathy, the medical term for swollen lymph nodes. These small, bean-shaped structures are part of the immune system, functioning as filters to trap harmful substances like bacteria and viruses. When an infection is present, lymph nodes swell as they produce white blood cells to fight off invaders.
A lump caused by a lymph node is typically soft, flexible, and tender or painful when touched. Common infectious causes that trigger this swelling include upper respiratory infections, strep throat, and ear infections. Dental issues, such as an abscessed tooth, gum disease, or recent dental work, also frequently cause localized lymph node swelling under the jaw.
The characteristics of these reactive lymph nodes are generally reassuring; they move freely beneath the skin and are often accompanied by other symptoms of infection, like a fever or sore throat. The swelling is transient, meaning it should resolve on its own, usually within two to four weeks, as the underlying infection clears. If the lump is only on one side, it often points directly to a localized issue in the mouth or throat on that same side.
Non-Lymph Node Sources of Submandibular Lumps
While lymph nodes are the usual suspects, other structures in the submandibular space can also form lumps. The submandibular salivary glands, located beneath the jaw, are a common source of non-lymph node masses. Salivary gland issues often present as a firm swelling that may become more noticeable when eating or anticipating food.
One of the most common salivary gland problems is sialolithiasis, a condition where calcified stones form and block the salivary ducts. This blockage leads to a painful backup of saliva, causing the gland itself to swell and feel like a firm lump. If the blockage leads to a bacterial infection of the gland, a condition called sialadenitis develops, which presents with rapid pain, swelling, and sometimes redness over the area.
Other benign growths in the soft tissue can also present as lumps under the jaw. A lipoma is a common type of benign tumor made of fatty tissue that feels soft, doughy, and is easily movable beneath the skin. Cysts, such as epidermoid or dermoid cysts, are sacs filled with fluid or debris and may also be felt as a painless lump. Less common, but still possible, are non-inflammatory conditions like sialadenosis, which is a painless enlargement of the salivary glands often linked to metabolic disorders.
Warning Signs Requiring Immediate Medical Review
Although most lumps under the jaw are benign, certain warning signs indicate that a lump requires immediate professional medical evaluation. Any lump that is hard to the touch, feels fixed, or is immobile is considered a red flag. Similarly, a lump that persists for longer than two to four weeks without showing signs of shrinking or resolving should be examined by a healthcare provider.
Other concerning symptoms that warrant urgent review include unexplained weight loss, night sweats, or a persistent fever. Additional warning signs are difficulty swallowing (dysphagia), voice changes, or persistent pain that is not typical of a common infection. These characteristics may suggest a less common cause, such as a tumor in the salivary glands or, rarely, a type of cancer like lymphoma.
A medical professional, such as a primary care physician or dentist, will typically perform a physical examination and take a thorough history to assess these characteristics. If the lump remains suspicious, they may recommend diagnostic tools like an ultrasound or CT scan to better visualize the mass. Early diagnosis is important for all conditions, ensuring that even rare cases are identified promptly and treated appropriately.