Swollen gums are almost always a sign of inflammation, and the most common trigger is bacterial plaque building up along your gumline. About 42% of U.S. adults over 30 have some form of periodontal disease, so if your gums look puffy, red, or tender, you’re far from alone. But plaque isn’t the only culprit. Hormonal shifts, certain medications, nutritional gaps, and infections can all cause gum tissue to swell.
Plaque Buildup and Early Gum Disease
The most likely reason your gums are swollen is gingivitis, the earliest stage of gum disease. It starts when a sticky film of bacteria (plaque) accumulates where your teeth meet your gums. Your immune system responds to those bacteria with inflammation, which is why the tissue turns red, puffs up, and bleeds easily when you brush or floss. The good news: gingivitis doesn’t damage bone, and it’s completely reversible with consistent brushing, flossing, and professional cleanings.
When gingivitis goes untreated, things escalate. Bacteria stay trapped along and beneath the gumline, and your body’s ongoing immune response causes the gums to pull away slightly from the teeth. These small gaps, called pockets, create a low-oxygen environment where more aggressive bacteria thrive. At this point the condition becomes periodontitis, an advanced form of gum disease where inflammation spreads below the gums and starts breaking down the bone and connective tissue that hold teeth in place. Unlike gingivitis, periodontitis involves bone loss the body can’t naturally replace. Teeth may loosen, shift, or become painful to chew on. Nearly 60% of adults 65 and older have periodontitis, according to national survey data from the NIDCR.
Hormonal Changes
Hormones directly affect gum tissue. During pregnancy, puberty, menstruation, and menopause, rising levels of estrogen and progesterone increase blood flow to the gums, making them more sensitive to even small amounts of plaque. Gum tissue actually has receptors for these hormones, which means it responds to hormonal shifts the way other reproductive tissues do. The result is swelling, tenderness, and bleeding that can seem out of proportion to how well you’re brushing.
Pregnancy gingivitis is especially common. The combination of elevated hormones and normal plaque exposure can cause noticeable changes in gum size and shape, typically peaking in the second trimester. The swelling usually improves after delivery, but keeping up with dental cleanings during pregnancy helps prevent it from progressing.
Medications That Enlarge Gum Tissue
Three classes of medication are well known for causing gum overgrowth, a condition where the tissue physically enlarges and may partially cover the teeth. These are certain anti-seizure drugs, calcium channel blockers used for blood pressure, and immunosuppressants used after organ transplants. Despite having completely different purposes, all three share the ability to trigger excess gum tissue growth. If you started a new medication and noticed your gums looking puffy or your teeth appearing smaller, that connection is worth raising with your prescriber.
Orthodontic appliances like braces or clear aligners can also irritate gum tissue enough to cause localized swelling, particularly if plaque accumulates around brackets or wires that are difficult to clean around.
Vitamin C and Nutritional Gaps
Severe vitamin C deficiency causes scurvy, which has long been associated with bleeding, swollen gums. But research from Harvard Health highlights that even mildly low vitamin C levels, well short of scurvy, are associated with increased gum bleeding. Vitamin C plays a key role in maintaining the integrity of blood vessels and connective tissue throughout the body, including in the gums. If your diet is low in fruits and vegetables, this could be a contributing factor, particularly if your swelling comes with gums that bleed at the slightest touch.
Infections and Abscesses
A sudden, localized area of swelling, especially one that’s painful and warm to the touch, may signal a dental abscess. This happens when bacteria invade the inner part of a tooth or the space between a tooth and the gum, forming a pocket of pus. The swelling can come on fast and may be accompanied by throbbing pain, a bad taste in your mouth, or sensitivity to hot and cold.
Most abscesses need professional drainage and treatment. If you develop a fever along with facial swelling, or if you have difficulty breathing or swallowing, that’s a sign the infection may be spreading into the jaw, throat, or neck, and it warrants emergency care.
Other Common Triggers
A few additional causes are easy to overlook:
- Aggressive brushing. A hard-bristled toothbrush or too much pressure can physically irritate and inflame gum tissue. Switching to a soft-bristled brush often helps within days.
- Food impaction. A piece of food wedged between teeth can cause localized gum swelling that resolves once the debris is removed with floss or an interdental pick.
- Tobacco use. Smoking reduces blood flow to the gums and weakens your immune response to bacteria, making gum disease more likely and harder to treat.
- Mouth breathing. Breathing through your mouth, especially at night, dries out gum tissue. Chronic dryness removes the protective effect of saliva and can leave gums swollen and irritated, particularly along the front teeth.
What Swollen Gums Are Telling You
Gum swelling that shows up once and resolves in a day or two, say after a popcorn kernel gets stuck, is usually nothing to worry about. Swelling that persists for more than a week, comes back repeatedly, or is accompanied by bleeding, pain, or a bad smell is your body flagging a problem that won’t fix itself. The earlier gum disease is caught, the simpler and less invasive the treatment. Once bone loss begins, it can’t be reversed without professional intervention.
If you can pinpoint a clear trigger like a new medication, pregnancy, or a rough spot on a dental restoration, that gives your dentist a head start. If you can’t, a standard cleaning and exam will usually identify whether plaque-driven inflammation is the issue and how far it’s progressed.