Infected Tooth Symptoms: How to Tell If You Have a Tooth Infection

A tooth infection occurs when bacteria invade the dental pulp, the living tissue inside your tooth. The resulting infection can cause intense throbbing pain, swelling, fever, and other symptoms that range from uncomfortable to dangerous. Knowing what to look for helps you act quickly and get the right treatment.

7 min readMedically reviewed contentLast updated March 20, 2026

Key Takeaways

  • The hallmark symptoms of an infected tooth are persistent throbbing pain, sensitivity to hot and cold, swelling in the face or gums, and a bad taste in the mouth.
  • A small bump on the gum near the affected tooth (called a fistula or gum boil) is a common sign that infection has formed an abscess at the root tip.
  • A tooth infection becomes a medical emergency if swelling spreads to the eye, throat, or neck, or if you develop difficulty breathing or swallowing.
  • An infected tooth will not heal on its own. Antibiotics may control the infection temporarily, but root canal treatment or extraction is needed to eliminate the source.
  • Untreated tooth infections can spread to the jaw, head, neck, and in rare cases, the bloodstream. Prompt treatment prevents serious complications.
  • An endodontist is the dental specialist trained to treat tooth infections through root canal therapy and related procedures.

Common Symptoms of an Infected Tooth

Tooth infection symptoms can appear suddenly or develop gradually over days to weeks. Some infections cause severe pain from the start. Others build slowly, with mild discomfort that worsens over time. Here are the most common symptoms.

Throbbing or Pulsating Pain

The most recognizable symptom of a tooth infection is a deep, throbbing pain that pulses in rhythm with your heartbeat. The pain may be constant or come and go. It often intensifies when you lie down because blood pressure to the head increases in a horizontal position. Over-the-counter pain relievers may dull it temporarily but typically do not eliminate it.

Swelling in the Face, Jaw, or Gums

Swelling is a sign that the infection has spread beyond the tooth into the surrounding tissues. You may notice swelling in the gum near the affected tooth, in the cheek, along the jawline, or under the eye depending on which tooth is infected. Upper teeth tend to cause swelling in the cheek or below the eye. Lower teeth often cause swelling along the jaw or under the chin.

Sensitivity to Hot and Cold

An infected tooth often becomes extremely sensitive to temperature. Hot food or drinks typically cause a sharp, lingering pain that lasts well after the stimulus is removed. Cold sensitivity may also occur. If sensitivity to heat lingers for more than 30 seconds after you remove the hot food or drink, that strongly suggests pulp involvement.

Pimple or Bump on the Gum

A small, pimple-like bump on the gum near the painful tooth is called a fistula (also known as a gum boil or parulis). This bump is a drainage point for pus from the infection at the root tip. It may come and go and may release a salty or foul-tasting fluid when it drains. A fistula on the gum is a reliable sign that an abscess has formed.

Other Symptoms to Watch For

  • Fever: A temperature above 100.4 F (38 C) can indicate the infection is affecting your body systemically.
  • Bad taste or bad breath: Pus draining from the infection causes a persistent foul taste in the mouth that brushing does not resolve.
  • Pain when biting or chewing: Pressure on the infected tooth pushes on the inflamed tissue at the root tip, causing sharp pain.
  • Tender or swollen lymph nodes: The lymph nodes under the jaw or in the neck may become swollen and tender to touch.
  • Tooth discoloration: An infected tooth may darken to a gray or brownish color as the pulp tissue inside dies.
  • Loose tooth: The infection can erode the bone around the root, causing the tooth to feel slightly mobile.

When a Tooth Infection Is an Emergency

Most tooth infections are painful but not immediately life-threatening. However, certain warning signs mean you should seek emergency care without delay. A dental infection that spreads can become dangerous rapidly.

Go to the Emergency Room If You Experience

A condition called Ludwig's angina occurs when infection from a lower tooth spreads into the floor of the mouth and throat. This can compromise the airway and requires immediate hospital treatment. While rare, it is the reason that significant swelling from a tooth infection should always be evaluated urgently.

  • Swelling that spreads to the floor of the mouth, throat, or neck (this can obstruct breathing)
  • Difficulty swallowing or opening your mouth fully (trismus)
  • Difficulty breathing
  • High fever above 101 F (38.3 C) with facial swelling
  • Swelling around or below the eye
  • Confusion, rapid heart rate, or feeling very unwell (signs of systemic infection)

What Causes a Tooth Infection?

A tooth infection starts when bacteria reach the pulp inside the tooth. Several pathways can lead to this.

  • Deep cavity: Untreated tooth decay that penetrates through the enamel and dentin into the pulp chamber.
  • Cracked or fractured tooth: A crack that extends into the pulp allows bacteria to enter.
  • Trauma: A blow to the tooth can damage or kill the pulp, even if the tooth appears intact on the outside.
  • Failed previous dental work: Old fillings or crowns that leak can allow bacteria to reach the pulp.
  • Gum disease: Severe periodontal disease can create a pathway for bacteria to infect the tooth through the root tip.

Types of Tooth Abscesses

A periapical abscess forms at the tip of the tooth root when the pulp dies and bacteria multiply at the root end. This is the most common type and the kind that endodontists treat with root canal therapy. A periodontal abscess forms in the gum tissue alongside the tooth root, typically related to gum disease. The symptoms can overlap, and a dentist or endodontist can determine the type through examination and X-rays.

Home Care Before Your Appointment

Home remedies do not cure a tooth infection. They can only manage discomfort until you receive professional treatment. If you cannot see a dentist or endodontist immediately, the following measures may help.

  • Over-the-counter pain relief: Ibuprofen (Advil, Motrin) reduces both pain and inflammation. Acetaminophen (Tylenol) can be alternated with ibuprofen for additional pain control. Follow package dosing instructions.
  • Saltwater rinse: Dissolve half a teaspoon of salt in 8 ounces of warm water and rinse gently. This can help draw pus toward the surface and provide temporary relief.
  • Cold compress: Apply an ice pack wrapped in a cloth to the outside of your cheek for 15-20 minutes at a time to reduce swelling.
  • Elevate your head: Sleep with an extra pillow to keep your head elevated, which can reduce throbbing.
  • Avoid hot food and drinks: Heat increases blood flow to the infected area and typically worsens pain.

What Not to Do

Do not apply aspirin directly to the gum or tooth. This causes a chemical burn to the tissue. Do not attempt to drain an abscess yourself, as this can spread the infection. Do not ignore worsening symptoms while waiting for an appointment. If pain or swelling increases significantly, seek urgent care.

How a Tooth Infection Is Treated

The only way to eliminate a tooth infection is to remove the source of bacteria. Antibiotics alone cannot cure the infection because they cannot penetrate the dead pulp tissue inside the tooth.

Root Canal Treatment

Root canal treatment removes the infected pulp, cleans and disinfects the canal system inside the tooth, and seals it to prevent reinfection. The tooth is then restored with a crown. This is the preferred treatment when the tooth can be saved. An endodontist, a specialist in treating the interior of teeth, typically performs root canals on infected teeth, especially complex cases.

Tooth Extraction

If the tooth is too damaged to save, extraction removes the infection along with the tooth. After healing, the missing tooth can be replaced with a dental implant, bridge, or partial denture. An oral surgeon or general dentist typically performs extractions.

The Role of Antibiotics

Antibiotics may be prescribed to help control the spread of infection, particularly if there is facial swelling, fever, or signs of systemic involvement. However, antibiotics treat the surrounding infection, not the source inside the tooth. They are a supplement to dental treatment, not a replacement for it. The infection will return if the tooth is not treated.

Treatment Cost for an Infected Tooth

Treatment costs depend on the type and location of the tooth and the complexity of the infection. Costs vary by location and provider.

An emergency exam with X-rays typically costs $100 to $300. Root canal treatment ranges from $700 to $1,500 for the root canal itself, with an additional $800 to $1,500 for the crown. Extraction costs range from $150 to $400 for a simple extraction or $200 to $600 for a surgical extraction.

Most dental insurance plans cover a significant portion of root canal treatment and extractions. Emergency exams are generally covered as well. If you need a dental implant to replace an extracted tooth, that is a separate cost and may or may not be covered by your plan.

When to See an Endodontist

An endodontist is a dentist with 2 to 3 years of additional specialty training in diagnosing and treating infections inside the tooth. While general dentists perform root canals, an endodontist is the specialist to see when the infection is severe, the tooth has complex anatomy, or a previous root canal has failed.

If you are experiencing symptoms of a tooth infection, the first step is to contact a dentist or endodontist promptly. Many endodontists keep same-day or next-day openings for emergency cases. You do not always need a referral; many endodontists accept patients directly.

Find an Endodontist Near You

Every endodontist on My Specialty Dentist has verified specialty credentials. Search by location to find endodontists in your area who treat tooth infections and perform root canal therapy.

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Frequently Asked Questions

Can an infected tooth heal on its own?

No. A tooth infection will not resolve without treatment. The pulp inside the tooth has a limited blood supply, and once bacteria have established an infection, the body cannot clear it. Antibiotics can temporarily reduce symptoms, but the infection returns unless the tooth is treated with a root canal or extraction.

How do I know if my tooth infection has spread?

Signs that a tooth infection is spreading include swelling that extends to the cheek, jaw, neck, or under the eye; fever; difficulty swallowing or breathing; swollen lymph nodes; and feeling generally unwell. If you notice any of these signs, seek emergency medical or dental care.

How long can a tooth infection go untreated?

There is no safe timeline for leaving a tooth infection untreated. Some infections progress slowly over weeks or months, while others spread rapidly within days. An infection that seems mild can worsen suddenly. The safest approach is to seek treatment as soon as you notice symptoms.

Will antibiotics cure a tooth infection?

Antibiotics alone cannot cure a tooth infection. They can help control the spread of infection in the tissues surrounding the tooth, but they cannot reach the dead or dying pulp inside the tooth where the bacteria originate. A root canal or extraction is needed to eliminate the source.

What does a tooth abscess look like?

A tooth abscess often appears as a small, round, pimple-like bump on the gum near the affected tooth. It may be red or yellowish-white. The surrounding gum tissue may be swollen and tender. If the abscess drains, you may notice a foul-tasting fluid in your mouth.

Should I go to the ER for a tooth infection?

Go to the emergency room if you have facial swelling that is spreading, difficulty breathing or swallowing, a high fever with swelling, or if you feel very unwell. For tooth pain without these danger signs, contact a dentist or endodontist for an urgent appointment rather than the ER, as emergency rooms can prescribe antibiotics but typically cannot perform the definitive dental treatment needed.

Sources

  1. 1.American Association of Endodontists. "Tooth Pain." AAE Patient Education.
  2. 2.Robertson D, Smith AJ. "The microbiology of the acute dental abscess." J Med Microbiol. 2009;58(Pt 2):155-162.
  3. 3.Bali RK, et al. "A review of complications of odontogenic infections." Natl J Maxillofac Surg. 2015;6(2):136-143.
  4. 4.American Dental Association. "Abscess (Toothache)." ADA MouthHealthy.
  5. 5.Lockhart PB, et al. "Evidence-based clinical practice guideline on antibiotic use for the urgent management of pulpal- and periapical-related dental pain and intraoral swelling." J Am Dent Assoc. 2019;150(11):906-921.

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