Swelling under the tongue, known as the floor of the mouth or sublingual space, can signal a variety of underlying issues. This area contains soft tissues, salivary ducts, and blood vessels, making it susceptible to swelling from multiple causes. The nature of the swelling—whether it is painful, sudden, or persistent—helps determine the source of the problem. Causes range from simple blockages to conditions that require immediate medical intervention.
Issues Affecting Salivary Glands
The majority of swelling under the tongue relates to the sublingual and submandibular salivary glands, which empty saliva into the mouth through small ducts. A common condition is Sialolithiasis, involving the formation of salivary stones (calcified deposits) within the ducts or the gland itself. These stones can partially or completely obstruct the flow of saliva.
The blockage causes saliva to back up inside the gland, leading to a painful lump and noticeable swelling. This swelling often intensifies during meals, particularly when consuming sour foods that stimulate saliva production. This intermittent pain occurs because the saliva cannot drain properly against the obstruction, causing the gland to enlarge.
When a salivary stone causes a prolonged obstruction, the stagnant saliva can lead to a secondary bacterial infection called Sialadenitis. This infection results in increased pain and swelling that does not subside after eating. Symptoms may include fever or the presence of pus draining into the mouth, often requiring antibiotic treatment.
Physical Injury and Localized Irritation
Direct physical trauma or sustained irritation is another source of sublingual swelling, often leading to localized bruising or inflammation. Accidental injury, such as biting the tongue or floor of the mouth, can cause immediate swelling and a localized collection of blood, known as a sublingual hematoma. Swelling can also occur as a complication following dental procedures or oral surgery.
Mechanical irritation from foreign objects, such as ill-fitting dental appliances or sharp edges on broken teeth, can cause chronic inflammation. Burns from hot food or liquids can also injure the delicate mucosa, resulting in temporary swelling and tissue damage. These causes are usually self-limited, resolving once the source of trauma or irritation is removed or the tissue heals.
Cysts and Acute Inflammatory Conditions
Swelling under the tongue can result from fluid-filled sacs or severe, rapidly progressing infections and systemic reactions. A Ranula is a type of mucocele that forms on the floor of the mouth, appearing as a soft, fluid-filled cyst. It occurs when saliva leaks out of a damaged sublingual salivary gland duct and accumulates in the surrounding tissue, often due to minor trauma or obstruction.
While usually painless, a Ranula can occasionally grow large enough to interfere with speech or swallowing. More urgent causes include severe localized infections like Ludwig’s Angina, a rapidly spreading cellulitis affecting the tissues of the floor of the mouth and neck. This bacterial infection, often originating from an infected tooth root, causes severe, fast-growing swelling that can push the tongue upward.
Another acute condition is Angioedema, a sudden swelling of the deep layers of the skin and mucous membranes, commonly affecting the tongue, lips, and face. This reaction results from the release of chemicals like histamine and is frequently triggered by allergic responses to medications, foods, or insect stings. Angioedema caused by specific medications, such as ACE inhibitors, can present without the typical itchy rash (hives).
Recognizing Serious Symptoms
While some causes of sublingual swelling are transient, certain signs indicate a medical emergency requiring immediate attention due to the risk of airway compromise. Any swelling that develops rapidly over minutes or hours, especially if accompanied by difficulty breathing or swallowing (dysphagia), signals a potentially life-threatening situation. The floor of the mouth is a confined space, and severe swelling here can obstruct the airway very quickly.
Other concerning symptoms include drooling, which suggests an inability to swallow saliva, and a muffled or altered speech pattern. The presence of systemic signs, such as fever, chills, or increasing pain, suggests a spreading infection, like Ludwig’s Angina, that requires urgent antibiotic treatment. If swelling under the tongue is accompanied by these severe symptoms, immediate medical evaluation is necessary to prevent serious complications.