A swollen gum usually means your body is fighting irritation or infection in the tissue around your teeth. The most common cause is plaque buildup along the gumline, but swelling can also come from an abscess, hormonal changes, certain medications, or a nutritional deficiency. Where the swelling is, how long it’s been there, and whether it hurts all help narrow down what’s going on.
Plaque Buildup and Early Gum Disease
The single most common reason for swollen gums is gingivitis, the earliest stage of gum disease. When plaque (a sticky film of bacteria) sits along the gumline for too long, it triggers inflammation. Your gums turn red, puff up, and bleed easily when you brush or floss. At this stage, no permanent damage has occurred. The tissue is irritated but the bone underneath is still intact.
If gingivitis goes untreated, it can progress to periodontitis, where the infection starts destroying the bone and connective tissue that hold your teeth in place. Dentists measure the depth of the pocket between your gum and tooth to assess severity. Healthy gums sit snugly against the tooth with pockets of 1 to 3 millimeters. In early periodontitis, pockets reach about 4 mm. In advanced stages, pockets deepen to 6 mm or more, and teeth can loosen or shift. The American Academy of Periodontology classifies periodontitis into four stages, with Stage III and IV involving significant bone loss and potential tooth loss.
The good news: gingivitis is completely reversible. Improving your brushing and flossing routine clears the plaque, and the inflammation calms down. After a professional deep cleaning, gums typically heal within 5 to 7 days, though some soreness and minor swelling may linger for the first few days after the procedure.
An Abscess or Infection
If the swelling is localized to one spot, feels like a firm or squishy bump, and throbs with pain, you may have a gum abscess. There are two main types. A periodontal abscess forms in the gum tissue itself, often in a deep pocket next to a tooth. A periapical abscess starts inside the tooth (from decay or a crack) and pushes infection out through the root into the surrounding gum. Both can cause intense, pulsing pain, a bad taste in your mouth, and swelling that seems to appear quickly.
Abscesses don’t resolve on their own. The infection needs to be drained, and you’ll likely need antibiotics or a root canal depending on where it originated. If swelling spreads to your jaw or face, you develop a fever, or you have difficulty swallowing or breathing, that’s a sign the infection is spreading beyond your mouth. That situation requires emergency care, not a scheduled appointment.
Hormonal Changes
Hormones play a surprisingly large role in gum health. During pregnancy, rising progesterone levels change how gum tissue responds to even small amounts of plaque. Progesterone acts as a mild immunosuppressant in the gums, dampening the body’s quick-response defenses while amplifying a slower, chronic inflammatory reaction. The result is gums that look dramatically swollen and inflamed even with a normal amount of bacteria present. Blood vessel growth increases in the tissue, which is why pregnant women often notice their gums bleed much more easily.
This “pregnancy gingivitis” is extremely common and typically peaks in the second trimester. Puberty, menstruation, and menopause can all cause similar (though usually milder) gum sensitivity due to hormonal fluctuations. The swelling generally improves once hormone levels stabilize, but keeping up with oral hygiene during these periods prevents it from progressing into something more permanent.
Medications That Cause Gum Overgrowth
Certain medications cause gum tissue to physically enlarge, a side effect called gingival overgrowth. The gums grow excess tissue that can partially cover the teeth, trap bacteria, and make cleaning difficult. Three main drug categories are linked to this:
- Blood pressure medications (calcium channel blockers): Amlodipine, nifedipine, diltiazem, and verapamil are among the most commonly reported. Nifedipine and amlodipine are particularly well-documented culprits.
- Anti-seizure medications: Phenytoin causes the most fibrotic (thickened, firm) type of gum overgrowth.
- Immunosuppressants: Cyclosporine, often used after organ transplants, causes highly inflamed gum enlargement.
If you recently started a new medication and noticed your gums swelling or growing over your teeth, that connection is worth raising with your prescriber. In some cases, switching to a different drug in the same class resolves the problem. Meticulous oral hygiene can slow the overgrowth but often isn’t enough on its own to reverse it.
Vitamin C Deficiency
Low vitamin C levels weaken the collagen that gives your gums their structure. Without enough collagen, gum tissue becomes fragile, swollen, and bleeds easily, even with gentle contact. Full-blown scurvy is rare in developed countries, but mild vitamin C deficiency is more common than most people realize, especially in people with very limited diets, smokers (who burn through vitamin C faster), and older adults.
Bleeding gums that don’t improve with better brushing and flossing can be an early signal that your vitamin C intake is too low. Adults need about 75 to 90 mg per day, roughly the amount in a single orange or a cup of strawberries.
Diabetes and Blood Sugar
Diabetes and gum disease have a two-way relationship. High blood sugar promotes the release of inflammatory molecules throughout the body, and gum tissue is especially vulnerable. Elevated glucose also impairs your immune system’s ability to fight off the bacteria that cause gum infections, so plaque does more damage faster. At the same time, poorly controlled blood sugar encourages more plaque to accumulate in the first place.
People with uncontrolled diabetes are significantly more likely to develop periodontitis, and the gum disease itself can make blood sugar harder to manage, creating a cycle that worsens both conditions. If you have diabetes and notice persistent gum swelling, getting your blood sugar under tighter control is one of the most effective things you can do for your gums.
Other Common Triggers
Not every swollen gum points to disease. Some everyday causes include:
- Food trapped under the gumline: A popcorn hull, seed, or piece of food wedged between the tooth and gum causes localized swelling that resolves once the debris is removed.
- Aggressive brushing: Using a hard-bristled toothbrush or pressing too hard can irritate and inflame gum tissue over time.
- A new dental appliance: Braces, retainers, or ill-fitting dentures can rub against the gums and cause swelling at the contact point.
- Wisdom teeth: Partially erupted wisdom teeth create a flap of gum tissue that easily traps bacteria, leading to a painful swelling called pericoronitis.
What the Swelling Is Telling You
The pattern of your swelling offers useful clues. Generalized puffiness across your upper or lower gums points toward gingivitis, a hormonal shift, or a medication side effect. A single swollen spot near one tooth suggests a localized infection, trapped food, or an abscess. Swelling that comes and goes with your menstrual cycle or appeared during pregnancy fits a hormonal pattern. And gum tissue that has slowly grown larger over months, especially if you take one of the medications listed above, points to drug-induced overgrowth.
Swelling that has lasted more than a week without improving, is accompanied by pus or a foul taste, or keeps coming back in the same spot is worth getting evaluated. A dentist can probe the gum pockets, take X-rays to check for bone loss, and determine whether the issue is surface-level irritation or something deeper.