If your mouth is swollen, the first thing to do is figure out whether it’s an emergency. Swelling that spreads to your throat or tongue, makes it hard to breathe or swallow, or comes with a rash can signal a severe allergic reaction that needs immediate medical attention. If you can breathe and swallow normally, you likely have time to assess what’s going on and treat it at home while deciding whether you need professional care.
Check for Signs of a Serious Reaction First
Sudden swelling of the lips, mouth, throat, or tongue can be a sign of anaphylaxis, a life-threatening allergic reaction. Call emergency services right away if you notice any of the following alongside mouth swelling: difficulty breathing or very fast breathing, wheezing or gasping, a tight feeling in your throat, trouble swallowing, a hoarse voice, or skin that turns blue, grey, or pale. On darker skin tones, color changes are often easier to spot on the palms of the hands or soles of the feet.
If you carry an epinephrine auto-injector, use it immediately. Even if symptoms seem to improve after using it, you still need emergency care because reactions can return.
Common Reasons Your Mouth Might Swell
Mouth swelling has a surprisingly wide range of causes, and figuring out which one applies to you helps determine what to do next.
Dental abscess: A bacterial infection at the root of a tooth or between the gum and tooth can cause swelling of the gum, jaw, or even the side of the face. The swelling is usually on one side, often painful, and may come with a persistent throbbing toothache or a bad taste in your mouth. Left untreated, the infection can spread to your jaw or other parts of your body.
Allergic reaction or angioedema: Food allergies, medication reactions, insect stings, or contact with an irritant can cause rapid swelling of the lips, tongue, or inner cheeks. Angioedema is a deeper form of swelling beneath the skin. About two-thirds of people who get this type of swelling from mast cell activation also develop hives elsewhere on the body. Some people experience angioedema as a side effect of blood pressure medications (ACE inhibitors), and this type does not come with hives.
Injury or trauma: Biting your cheek or lip hard, a blow to the face, or a burn from hot food can all produce localized swelling. A bruise (hematoma) inside the cheek from trauma typically resolves within about two weeks with basic care.
Oral surgery: Swelling after a tooth extraction or other dental procedure is normal and follows a predictable pattern. It peaks within one to two days, begins to go down around days three to five, and is mostly gone by seven to ten days.
Blocked salivary gland: A small stone can block one of your salivary ducts, causing swelling on one side of your mouth or under your jaw. The hallmark symptom is swelling and pain that gets worse during meals, when saliva production increases, and then gradually eases between meals.
Immediate Steps You Can Take at Home
Regardless of the cause, a few simple measures can reduce swelling and discomfort while you figure out your next move.
Apply a cold compress. Place a cold pack or a bag of ice wrapped in a cloth against the outside of your cheek or lip near the swollen area. Use it in intervals of 15 to 20 minutes on, then 15 to 20 minutes off. Cold helps constrict blood vessels and limits how much fluid builds up in the tissue. This is especially effective in the first 24 to 48 hours after an injury or surgery.
Rinse with warm salt water. Dissolve half a teaspoon of salt in a cup of warm water and gently swish it around your mouth for 30 seconds before spitting it out. Salt water helps clean the area, reduces bacteria, and can soothe irritated tissue. You can repeat this several times a day.
Take an over-the-counter anti-inflammatory. Ibuprofen can help reduce both pain and swelling. Take it with food to avoid stomach irritation. Avoid anti-inflammatory pain relievers if you have a history of stomach ulcers, kidney problems, heart disease, or if you’re pregnant. Acetaminophen is a safer alternative for pain relief in those situations, though it won’t reduce inflammation.
For a blocked salivary gland, try gently massaging the swollen area and sucking on something sour, like a lemon drop. Sour flavors stimulate saliva production, which can help push a small stone through the duct. Most salivary stones resolve with this kind of conservative approach combined with anti-inflammatory medication.
When You Need Professional Help
Swelling from a minor bite or burn that stays small and starts improving within a day or two is usually fine to manage on your own. But several situations call for a dentist, doctor, or emergency room visit.
A dental abscess always requires professional treatment. The infection won’t clear up on its own. Your dentist will need to drain the abscess and may perform a root canal or extract the tooth depending on the damage. Antibiotics are prescribed when the infection has spread beyond the immediate area or if you have a weakened immune system. If you notice swelling along your jawline or face alongside a toothache, contact your dentist as soon as possible. Many dental offices have after-hours emergency lines for exactly this situation.
If your dentist’s office is closed and you’re dealing with severe pain, uncontrolled bleeding, or rapidly worsening swelling, go to an urgent care center or emergency room. The ER can manage your symptoms and stabilize an infection until you can see a dentist. Go directly to the ER if you have any broken facial bones or if swelling is affecting your ability to breathe or swallow.
For post-surgical swelling, contact your oral surgeon if the swelling hasn’t started to improve after five days, if it suddenly gets worse after initially improving, or if you develop a fever. These can be signs of a secondary infection at the surgical site.
Allergic Swelling and What Comes Next
If your mouth swelling came on suddenly and you suspect an allergy, an over-the-counter antihistamine can help with mild cases, particularly when hives are also present. Remove or avoid whatever you think triggered the reaction, whether it was a food, a new lip product, or a medication.
Recurrent episodes of lip or mouth swelling without an obvious trigger deserve medical investigation. Some people have hereditary angioedema, a genetic condition that causes unpredictable episodes of deep tissue swelling. Others develop angioedema as a side effect of ACE inhibitor blood pressure medications, sometimes months or even years after starting the drug. If you’ve had more than one unexplained episode, an allergist can run tests to identify the underlying cause and help you develop a plan to prevent future reactions.