Gum swelling is almost always caused by inflammation, and the most common trigger is bacterial plaque building up along the gumline. But plaque isn’t the only culprit. Hormonal shifts, infections, certain medications, and underlying health conditions can all make your gums puff up, turn red, or bleed. About 42% of American adults over 30 have some form of gum disease, so if you’re dealing with swollen gums, you’re far from alone.
Plaque Buildup and Early Gum Disease
The number one cause of gum swelling is gingivitis, the earliest stage of gum disease. It starts when a sticky film of bacteria (plaque) collects on your teeth, especially near the gumline. If that plaque isn’t removed through brushing and flossing, your immune system treats it as a threat and sends inflammatory cells to the area. This process kicks in fast. The initial inflammatory response begins within four or five days of plaque accumulation, bringing increased fluid and white blood cells to the gum tissue.
At this stage, your gums may look redder than usual, feel tender, and bleed when you brush or floss. The good news is that gingivitis is fully reversible. Improving your brushing and flossing routine can resolve the swelling within a couple of weeks. Left alone, though, the inflammation becomes chronic. Over time, it can destroy the ligaments and bone that hold your teeth in place, progressing into periodontitis, a more serious condition that affects nearly 60% of adults over 65.
Periodontitis: When Swelling Signals Deeper Damage
Periodontitis develops when gingivitis goes untreated and the infection moves below the gumline. Bacteria start forming pockets between your teeth and gums. In a healthy mouth, the space between your gum and tooth measures about 1 to 3 millimeters. Once pocket depths reach 4 millimeters or more, it’s a sign that tissue and bone are breaking down. The swelling at this point isn’t just surface irritation. It reflects an active infection eroding the structures that support your teeth.
Symptoms often include persistent swelling, gums that pull away from the teeth, bad breath that won’t go away, and teeth that feel loose or shift position. Periodontitis can’t be reversed at home. It requires professional cleaning below the gumline and, in advanced cases, surgical intervention to restore lost tissue.
Hormonal Changes
Hormones play a surprisingly large role in gum health. During pregnancy, rising progesterone levels increase blood flow throughout the body, including to the gums. That extra blood flow makes gum tissue more reactive to plaque, and the immune system responds more aggressively than it normally would, amplifying inflammation and bleeding. This is common enough to have its own name: pregnancy gingivitis. It typically appears in the second trimester and resolves after delivery, but it still needs attention because the inflammation can worsen existing gum problems.
Pregnancy isn’t the only hormonal trigger. Puberty, menstruation, menopause, and hormonal birth control can all cause temporary gum swelling through similar mechanisms. The gums become more sensitive to bacteria that would normally cause little reaction.
Smoking and Diabetes
Smoking is one of the strongest risk factors for gum disease. Among current smokers, 62.4% have periodontitis, compared to 34.4% of people who have never smoked. Tobacco reduces blood flow to the gums, weakens immune defenses against bacterial infection, and slows healing. It also masks warning signs: smokers are less likely to notice bleeding gums because nicotine constricts blood vessels, so the disease can progress further before they realize something is wrong.
Diabetes is another major contributor. About 60% of adults with diabetes have periodontal disease, compared to roughly 40% of those without it. High blood sugar creates an environment where bacteria thrive and the body’s ability to fight gum infections is impaired. The relationship runs both ways: gum disease can make blood sugar harder to control, and poorly managed blood sugar makes gum disease worse.
Infections and Abscesses
Sometimes gum swelling appears suddenly in one specific spot rather than across the whole gumline. This often points to a localized infection. A dental abscess, a pocket of pus caused by bacterial infection, can form at the root of a tooth or in the gum tissue itself. It typically looks like a swollen, pimple-like bump and may cause throbbing pain that radiates into the jaw or ear.
Abscesses don’t resolve on their own. The infection needs to be drained and treated. If you notice pus, a foul taste in your mouth, or swelling that comes on quickly in one area, that’s a sign to get dental care promptly rather than waiting it out.
Medications That Cause Gum Swelling
Certain medications can cause a condition called gingival overgrowth, where the gum tissue literally enlarges. The most common offenders are anti-seizure medications (particularly phenytoin), calcium channel blockers used for high blood pressure, and immunosuppressant drugs taken after organ transplants. The swelling tends to start between the teeth and can become pronounced enough to partially cover the tooth surfaces. If you’ve noticed gum changes after starting a new medication, your doctor may be able to adjust your prescription or switch to an alternative.
Other Common Triggers
Several everyday factors can also cause your gums to swell:
- Vitamin deficiencies. Low vitamin C (scurvy) directly causes gum swelling and bleeding. Vitamin K deficiency can also contribute to gum problems.
- Ill-fitting dental appliances. Dentures, braces, or retainers that rub against the gums create chronic irritation and localized swelling.
- Food impaction. A piece of food, especially something sharp like a popcorn hull, stuck between the gum and tooth can trigger rapid swelling in that spot.
- Viral infections. Herpes simplex and other viral infections can cause painful, swollen gums, particularly in children experiencing their first outbreak.
Reducing Swelling at Home
For mild gum swelling caused by plaque buildup or minor irritation, a saltwater rinse can help. Mix 1 teaspoon of salt into 8 ounces of warm water and swish gently for 30 seconds. If that feels too strong, cut back to half a teaspoon. Salt water helps draw out excess fluid from inflamed tissue and creates an environment that’s less hospitable to bacteria. You can do this two or three times a day.
Gentle but thorough brushing twice daily with a soft-bristled toothbrush, combined with daily flossing, addresses the root cause of most gum swelling. Switching to a soft brush matters because medium or hard bristles can further irritate swollen tissue. If your gums bleed when you floss, that’s actually a sign you need to keep flossing, not stop. The bleeding typically diminishes within a week or two as inflammation decreases.
Signs That Need Prompt Attention
Most gum swelling is manageable, but certain symptoms signal something more serious. Swelling that spreads from your gums toward your face, jaw, or neck can indicate an infection moving into deeper tissues. In rare cases, this kind of spreading infection can compromise your airway. A fever alongside gum swelling suggests the infection may be entering your bloodstream. Severe pain that intensifies rather than improving, visible pus, and difficulty eating or speaking are all reasons to seek care quickly rather than relying on home remedies.