Inflamed gums are most often caused by a buildup of bacterial plaque along the gumline, which triggers your body’s immune response against the growing bacteria. Over 42% of American adults aged 30 and older have some form of gum disease, making it one of the most common health conditions that goes undertreated. But plaque isn’t the only culprit. Hormonal shifts, certain medications, nutritional gaps, and chronic conditions like diabetes can all drive or worsen gum inflammation.
How Plaque Triggers Inflammation
Your mouth is home to hundreds of bacterial species, most of which are harmless. Problems start when bacteria accumulate into a sticky film called plaque, particularly along and just beneath the gumline. Your immune system recognizes this bacterial buildup as a threat and sends inflammatory signals to the area, increasing blood flow and deploying white blood cells to fight the infection. That’s what produces the redness, swelling, and bleeding you notice when brushing or flossing.
This response is actually your body trying to protect you. But if the plaque stays in place, the inflammation becomes chronic rather than temporary. Gum tissue that stays inflamed for weeks or months begins to pull away from the teeth, forming deeper pockets where even more bacteria collect. Those pockets can eventually reach a centimeter or more in depth, at which point the condition has progressed from gingivitis (reversible inflammation) to periodontitis (structural damage to the bone and tissue supporting your teeth).
The key detail here: not everyone’s immune system reacts the same way to the same amount of plaque. Some people develop severe inflammation with relatively little buildup, while others tolerate more plaque before their gums respond. This variation in immune response is a major reason why two people with similar brushing habits can have very different gum health.
Hormonal Changes During Pregnancy and Puberty
Rising levels of progesterone and estrogen, particularly during pregnancy, increase blood flow to gum tissue and alter how your immune system responds to plaque bacteria. The result is gums that swell, redden, and bleed more easily, even if your oral hygiene hasn’t changed. This is common enough to have its own name: pregnancy gingivitis.
Researchers believe progesterone plays a dual role, both amplifying the inflammatory signals sent by immune cells and changing which bacteria thrive in the mouth. The exact mechanisms are still being mapped, but the clinical pattern is well established. Puberty, menstruation, and menopause can produce similar effects on a smaller scale, making gums temporarily more sensitive during hormonal shifts.
Diabetes and Blood Sugar
Diabetes and gum disease have a two-way relationship. Persistently high blood sugar weakens the body’s ability to fight infection and promotes chronic inflammation throughout the mouth. Elevated glucose in saliva also feeds harmful oral bacteria, accelerating plaque buildup and making gum tissue more vulnerable to breakdown. According to Harvard School of Dental Medicine, this combination of impaired immunity and bacterial overgrowth is why people with diabetes face significantly higher rates of periodontal disease.
The relationship runs in both directions. Chronic gum inflammation releases inflammatory compounds into the bloodstream that can worsen insulin resistance, making blood sugar harder to control. Treating gum disease in people with diabetes has been shown to reduce systemic inflammation and improve metabolic health, which is why dental care is considered part of diabetes management.
Medications That Cause Gum Overgrowth
Certain prescription drugs can cause gum tissue to enlarge and swell independent of plaque buildup. Three drug classes are most frequently responsible:
- Seizure medications: Phenytoin is the most common offender, though other anticonvulsants can also trigger overgrowth.
- Blood pressure medications: Calcium channel blockers, especially nifedipine and amlodipine, are well-documented causes of gum enlargement.
- Immunosuppressants: Cyclosporine, commonly prescribed after organ transplants, is the most frequent cause in this category. Related drugs like tacrolimus produce less severe effects but can still contribute.
The overgrown tissue creates folds and pockets that trap bacteria, making standard brushing less effective and layering infection-driven inflammation on top of the drug-induced swelling. If you’re taking one of these medications and notice your gums growing over your teeth, your doctor may be able to adjust your prescription or switch to an alternative.
Vitamin C Deficiency
Vitamin C is essential for maintaining the connective tissue that holds your gums together. When levels drop low enough, gums become swollen, spongy, and bleed easily. Severe deficiency (scurvy) is rare in developed countries but not as uncommon as you might think. A UK survey found that 25% of men and 14% of women in low-income populations had vitamin C levels below the deficiency threshold of 11 micromoles per liter, with another 20% in the depleted range.
You don’t need to reach full-blown scurvy for low vitamin C to affect your gums. Suboptimal levels impair your body’s ability to repair and maintain gum tissue, making existing inflammation slower to heal. The normal reference range for vitamin C in blood is roughly 26 to 84 micromoles per liter. If your gums are persistently inflamed despite good oral hygiene, a nutritional gap is worth considering.
Smoking and Tobacco Use
Smoking is one of the strongest risk factors for gum disease. Nicotine constricts blood vessels in gum tissue, reducing the flow of oxygen and immune cells needed to fight bacterial infection. This makes smokers more susceptible to plaque-driven damage while simultaneously slowing healing.
There’s a deceptive element to this: because nicotine restricts blood flow, smokers often experience less visible bleeding, one of the earliest warning signs of gum inflammation. The disease can progress further before it becomes obvious. Smokers are also less responsive to gum treatment, meaning the same cleaning and hygiene improvements that reverse inflammation in nonsmokers often produce slower, less complete results.
Gingivitis vs. Periodontitis
Gum inflammation exists on a spectrum. Gingivitis is the early, reversible stage. Your gums are red and may bleed when you brush, but the underlying bone and connective tissue are still intact. With consistent brushing, flossing, and professional cleaning, mild gingivitis can resolve in as little as 7 to 10 days.
Periodontitis is what happens when gingivitis goes unchecked. The pockets between your teeth and gums deepen, bacteria colonize below the gumline where brushing can’t reach, and the bone supporting your teeth starts to break down. This stage is not fully reversible. Treatment can halt the progression and restore some tissue, but lost bone doesn’t grow back on its own. Among American adults over 30, about 34% have mild to moderate periodontitis and nearly 8% have the severe form.
Other Common Contributors
Aggressive brushing with a hard-bristled toothbrush can physically irritate gum tissue, producing inflammation that mimics or worsens plaque-driven disease. Mouth breathing, especially during sleep, dries out gum tissue and reduces the protective effect of saliva, allowing bacteria to accumulate faster. Poorly fitting dental appliances like dentures, retainers, or crowns can press against gums and create chronic irritation points.
Stress also plays a role, though indirectly. Elevated stress hormones suppress immune function, making your body less effective at managing the bacterial load in your mouth. People under chronic stress also tend to neglect oral hygiene and make dietary choices that promote inflammation, compounding the biological effect.