The most reliable sign of a tooth infection is a persistent, throbbing pain that doesn’t go away on its own and often intensifies when you bite down or press on the tooth. But pain is only one piece of the picture. Tooth infections can also announce themselves through swelling, bad taste in your mouth, sensitivity to heat or cold, and visible changes in your gums. Knowing which signs point to infection, and which signal that it’s spreading, can help you act before a treatable problem becomes a dangerous one.
The Main Symptoms of a Tooth Infection
Tooth infections don’t always start dramatically. You might first notice a dull ache that sharpens over a few days, or a tooth that suddenly becomes sensitive to hot drinks or cold air. As the infection grows, the pain typically becomes throbbing and constant rather than occasional. It can wake you up at night and make chewing on that side of your mouth nearly impossible.
Beyond pain, there are several other signs that point to infection:
- Swelling in the gum, cheek, or jaw near the affected tooth, which may feel warm to the touch
- A pimple-like bump on your gum (sometimes called a gum boil), which is the body’s attempt to drain the infection. These bumps are typically yellow, red, or pink and may ooze pus if you press on them.
- A foul or salty taste in your mouth, caused by pus draining from the infection site
- Sensitivity to pressure, meaning the tooth hurts when you tap on it or clench your teeth together
- Bad breath that doesn’t improve with brushing
If the infected tooth is in your upper jaw, the pain can radiate into your lower jaw, your ear, and your neck. This “referred pain” can make it hard to pinpoint exactly which tooth is the problem, which is one reason dental X-rays are so useful for diagnosis.
Two Types of Tooth Infection
Not all tooth infections start in the same place, and the type determines what you’ll feel and where.
A periapical abscess forms inside the tooth, near the nerve and around the tip of the root. It typically starts when bacteria enter through a cavity, crack, or chip in the enamel and work their way deep into the tooth’s inner tissue. The pain tends to be centered on one specific tooth and may feel like it’s coming from deep within.
A periodontal abscess starts in the gums rather than the tooth itself. It develops in the tissues that surround and support the tooth, often as a result of gum disease or an injury to the gum tissue. You’re more likely to see visible swelling along the gumline, and the pain may feel broader or less pinpointed than with a periapical abscess. Both types are serious and need treatment, but the approach your dentist takes will differ depending on which one you have.
What a Dentist Looks For
When you go in with a suspected infection, the exam is usually straightforward. Your dentist will tap on the tooth and press on the surrounding gum to check for pain responses. A tooth with an abscess at its root is generally sensitive to touch or pressure. They’ll also look for that telltale gum boil, which appears as a small raised bump, sometimes with visible drainage.
An X-ray is the standard next step. It can reveal an abscess at the root tip that isn’t visible from the outside, and it helps your dentist determine whether the infection has started to affect the surrounding bone. If there’s concern that the infection has spread beyond the tooth into your jaw or neck, a CT scan may be used to assess how far it’s gone.
Signs the Infection Is Spreading
Most tooth infections stay localized, but an untreated abscess can spread to the jaw, the head and neck, and in rare cases throughout the entire body. This is where things become genuinely dangerous.
If an infected upper tooth sits near the maxillary sinus (the large space behind your cheeks and under your eyes), the infection can create an opening into that sinus cavity. This leads to a sinus infection on top of the dental problem. If the abscess doesn’t drain at all, bacteria can migrate into deeper tissue spaces in the neck or travel through the bloodstream.
Seek immediate care if you notice any of these red flags:
- Fever, chills, or shivering
- Difficulty opening your mouth (a condition called trismus)
- Swelling that spreads to your eye, the floor of your mouth, or down your neck
- Difficulty breathing or swallowing
- A rapid pulse or feeling generally unwell
These are signs of systemic infection, meaning bacteria have moved beyond the tooth. Sepsis, a life-threatening response to infection that affects the whole body, is a real possibility with untreated dental abscesses. People with weakened immune systems face even higher risk of these complications.
How Tooth Infections Are Treated
The American Dental Association’s current guidelines emphasize something that surprises many people: antibiotics alone are not the standard treatment for most tooth infections. For a localized abscess without fever or signs of spreading, the recommended approach is direct dental treatment, not a prescription. That means draining the abscess, performing a root canal to remove infected tissue from inside the tooth, or extracting the tooth if it can’t be saved. Over-the-counter pain relievers like ibuprofen and acetaminophen are recommended for managing discomfort.
Antibiotics enter the picture only when the infection shows signs of systemic involvement, such as fever or general malaise. This matters because unnecessary antibiotics contribute to resistance and don’t actually resolve the source of infection. The bacteria are trapped inside the tooth or gum tissue, where antibiotics can’t effectively reach them. The physical source of infection has to be removed.
If you’re dealing with a periapical abscess, a root canal clears out the infected nerve tissue and seals the tooth. For a periodontal abscess, the dentist drains the pocket of infection and cleans the area around the gum and root surface. Recovery from either procedure typically involves a few days of soreness that’s manageable with pain relievers. Most people return to normal eating within a week.
What Sets Infection Pain Apart
It’s easy to confuse a tooth infection with other kinds of dental pain, so here’s what makes infection distinct. Sensitivity that only lasts a second or two when you drink something cold, then fades completely, is more likely related to enamel wear or a small cavity. Infection pain tends to linger. It sticks around after the trigger is gone. It throbs on its own, especially at night when you’re lying down and blood flow to your head increases.
Another distinguishing feature is that infection pain often gets worse over days rather than staying the same. A cracked tooth might cause sharp pain when you bite a certain way, but the baseline discomfort between episodes stays relatively stable. With an infection, the baseline keeps climbing as the abscess grows and pressure builds inside the tooth or gum tissue. If your pain is escalating day over day, that pattern alone is a strong signal that infection is involved.