A tooth infection usually announces itself with a persistent, throbbing pain that doesn’t fade on its own and often gets worse over hours or days. Unlike a regular toothache from sensitivity or a minor cavity, an infected tooth produces a distinct cluster of symptoms, from facial swelling to a foul taste in your mouth, that signal bacteria have moved deeper into or around the tooth. Here’s how to recognize what’s happening and what to expect next.
The Core Symptoms of an Infected Tooth
The most reliable sign is a severe, constant, throbbing toothache that can radiate into your jawbone, neck, or ear. This isn’t the sharp, momentary zing you get from biting into something cold. It lingers, sometimes for hours, and tends to intensify when you’re lying down at night because blood pressure shifts toward your head.
Beyond pain, watch for these signs:
- Sensitivity to hot and cold that feels more intense or longer-lasting than usual
- Pain when chewing or biting, especially when pressing down on a specific tooth
- Swelling in the face, cheek, or neck
- Tender, swollen lymph nodes under your jaw or along the side of your neck
- Fever
- A foul smell or taste in your mouth, sometimes described as bitter or salty
One particularly telling sign: a sudden rush of foul-tasting, salty fluid in your mouth followed by pain relief. That’s an abscess rupturing and draining on its own. The pain drops because the pressure is released, but the infection is still present and needs treatment.
What You Might See in Your Mouth
If you open wide and look in a mirror, an infected tooth can produce visible changes in the surrounding gum tissue. The gums near the affected tooth often appear red and swollen. In some cases, a small raised bump forms on the gum, sometimes called a gum boil. This is a pocket of pus pushing toward the surface. It may ooze a whitish or yellowish discharge if you press on it or even on its own.
Not every tooth infection creates a visible bump, though. Infections that start deep inside the tooth, near the root tip, can exist for weeks before anything shows on the surface. The absence of a visible sore doesn’t mean the tooth is fine.
Two Types of Tooth Infection
Not all tooth infections start the same way, and knowing the difference helps you understand what your dentist tells you.
A periapical abscess is the most common type. It begins inside the tooth itself, usually when bacteria reach the inner tissue (the pulp) through a deep cavity, crack, or chip in the enamel. If untreated, the infection travels down through the root and forms a pocket of pus at the root tip. The name literally means “around the apex” of the root. You’ll typically feel deep, throbbing pain centered on one tooth, and the tooth may feel slightly raised or loose.
A periodontal abscess starts in the gum tissue alongside the tooth root rather than inside the tooth. It’s usually related to gum disease or an injury to the gum. The pain tends to be more localized to the gum itself, and you’re more likely to see visible swelling or a pus-filled bump along the gum line. Pressing on the swollen area often produces a sharp increase in pain.
Signs the Infection Is Spreading
A tooth infection that stays contained around the tooth is painful but manageable with dental treatment. The concern is when bacteria enter the bloodstream or spread into surrounding tissue. Your body sends clear signals when this is happening.
Early systemic signs include feeling generally unwell: headache, fatigue, dizziness, and a low-grade fever with chills and sweating. These are easy to mistake for a cold or flu, but if they appear alongside a toothache, the connection is important. As things progress, you may notice a faster heart rate, rapid breathing (more than 25 breaths per minute), stomach pain, nausea, or signs of dehydration like dark urine and confusion.
Facial swelling that makes it difficult to fully open your mouth, swallow, or breathe is the most urgent warning sign. Swelling in the floor of the mouth or along the neck can compress your airway. This is a medical emergency, not a “wait until Monday” situation. Go to an emergency room.
How Dentists Confirm the Infection
Your dentist won’t rely on symptoms alone. A clinical exam typically starts with tapping on the suspected tooth. If a sharp tap sends a bolt of pain through the tooth, that’s a strong indicator of infection around the root. They may also apply heat or cold directly to the tooth to test whether the nerve inside is still alive. A tooth that doesn’t respond to temperature at all often has a dead or dying nerve, which points to an infection that has killed the pulp tissue.
The most definitive tool is an X-ray. Infection around a root tip causes the surrounding bone to break down, which shows up as a dark shadow at the base of the tooth. Dentists call this a periapical radiolucency. It’s essentially a hole in the bone where pus and inflamed tissue have replaced healthy structure. This finding, combined with your symptoms and the clinical tests, gives a clear diagnosis.
What Treatment Looks Like
The most important thing to know: antibiotics alone don’t fix an infected tooth. Current guidelines from the American Dental Association state that antibiotics are not needed for the majority of dental infections in otherwise healthy adults when a dentist can provide direct treatment. The infection lives inside the tooth or in a walled-off pocket of pus, and antibiotics can’t effectively penetrate those spaces.
The actual fix involves removing the source of infection. That means one of three things: draining the abscess, performing a root canal to clean out the infected tissue inside the tooth, or extracting the tooth entirely. Your dentist will recommend one based on how much healthy tooth structure remains and how far the infection has spread.
Antibiotics are reserved for specific situations: when the infection has spread beyond the tooth into surrounding tissue, when you have systemic signs like fever and facial swelling, or when dental treatment can’t happen right away and the infection needs to be held in check. Even then, the standard course is short, typically three to seven days, and your dentist will reassess after about three days.
Recovery After Treatment
Most people fully recover from a tooth infection within one to two weeks, depending on the severity and the treatment approach. After an abscess is drained, you can feel dramatically better within a few days once that built-up pressure is released. Swelling typically starts going down within 48 to 72 hours of treatment regardless of the method.
After a root canal, expect some soreness for about five to seven days, but most people return to normal activities immediately. An extraction takes a bit longer to heal, usually up to two weeks, as the gum and bone gradually fill in the empty socket. During this window, you’ll want to eat soft foods and keep the area clean to avoid reinfection.
If your pain gets worse instead of better after treatment, or if swelling returns, that’s a sign the infection wasn’t fully cleared and you need a follow-up visit promptly.