5 Warning Signs of Tooth Infection Spreading to the Body

A tooth infection begins when bacteria enter the inner layers of a tooth — usually through decay, a crack, or damaged gum tissue. Left untreated, the infection can move beyond the tooth into surrounding tissues and, in rare cases, into the bloodstream. Recognising the signs of tooth infection early is the best way to prevent complications and protect your health.

The good news is that most dental infections respond well to prompt treatment. When caught early, a course of treatment from an emergency dentist can stop the spread quickly. This guide explains the warning signs of tooth infection, how to spot signs of tooth infection spreading, and what to do if you suspect infection after dental treatment.

If you are experiencing dental pain or swelling right now, our complete guide to dental emergencies in London explains how to access urgent care. You can also learn more about dental abscess treatment on our services page.

What Are the Early Signs of Tooth Infection?

The early signs of tooth infection include persistent throbbing pain, sensitivity to hot and cold, swelling around the affected tooth, a bad taste in the mouth, and mild facial tenderness. You may also notice darkening of the tooth or a small pimple-like bump on the gum. These warning signs of tooth infection should not be ignored, as early treatment prevents further spread.

Understanding the signs of tooth infection at an early stage helps you act quickly. Pain is usually the first indicator. It may start as a dull ache and progress to sharp, throbbing discomfort that worsens at night or when biting down.

Signs of an infected tooth nerve often include lingering sensitivity long after exposure to temperature changes. If the nerve inside the tooth becomes inflamed or dies, pain may become constant. This is a clear signal that the infection has reached deeper tissues.

Signs of tooth infection after filling can appear days or weeks following dental work. A filling that sits too close to the nerve or does not seal properly may allow bacteria to reach the pulp. If you notice increasing sensitivity or throbbing around a recently filled tooth, arrange an assessment.

Signs of wisdom tooth infection are common in younger adults. Partially erupted wisdom teeth create pockets where food and bacteria collect. Swelling at the back of the jaw, difficulty opening the mouth, and pain radiating to the ear are typical symptoms.

For more detail on nerve-related dental pain, read our guide on understanding tooth nerve pain. If your wisdom teeth are causing problems, our wisdom tooth pain relief service can help.

5 Warning Signs of Tooth Infection Spreading to the Body

When a dental infection is left untreated, it can progress beyond the tooth and jaw. The following five warning signs suggest the infection may be spreading. Recognising these signs of tooth infection spreading early makes a significant difference to treatment outcomes.

1. Increasing Facial or Jaw Swelling

Localised swelling near a painful tooth is a common sign of abscess formation. However, when that swelling begins to spread — across the cheek, under the eye, or along the jawline — it suggests the infection is moving into deeper tissue layers.

Facial swelling caused by infection may feel warm to the touch and firm. The skin over the area can appear red or taut. This type of spreading inflammation requires urgent attention.

If you notice increasing facial swelling alongside dental pain, do not wait for it to settle on its own. Prompt assessment can prevent the infection from progressing. Learn more about how a dental abscess is treated at our practice.

2. Fever and Feeling Unwell

A tooth infection that remains contained within the mouth does not usually cause a fever. When you develop a raised temperature alongside dental pain or swelling, it can mean the body is fighting a more widespread infection.

Feeling generally unwell — fatigued, shivery, or light-headed — alongside dental symptoms is something to take seriously. These are potential signs of sepsis from tooth infection in their earliest stages. Sepsis occurs when the body's response to infection starts to affect normal organ function.

Signs of blood infection from tooth issues can include a rapid heartbeat, feeling confused, and extreme fatigue. These symptoms warrant urgent assessment. The important thing to remember is that early treatment almost always prevents serious complications.

Our article on the dangers of ignoring a dental abscess explains how untreated infections can progress and why timely care matters.

3. Difficulty Swallowing or Opening the Mouth

When a tooth infection spreads into the tissues around the throat or the muscles used for chewing, it can become difficult to swallow or fully open your mouth. This is known as trismus.

Difficulty swallowing — especially if accompanied by swelling in the floor of the mouth or under the tongue — is a sign that the infection has moved into an area that could compromise your airway. This requires same-day assessment.

If you are struggling to open your mouth or swallow comfortably, contact our out of hours dentist service for guidance.

4. Persistent Severe Pain

Dental pain that does not respond to over-the-counter painkillers, or that spreads beyond the original tooth, is a warning sign. When infection progresses, the pain often becomes constant rather than intermittent.

Pain radiating into the ear, temple, or down the neck suggests the infection is affecting a wider area. These are clear signs of tooth infection spreading that should prompt you to seek professional care.

Untreated infection can damage surrounding bone and tissue, making later treatment more complex. Addressing pain early leads to simpler, more comfortable outcomes.

If you are in severe pain, our severe toothache relief page explains how we can help today.

5. Swelling Under the Jaw or Neck

Swelling that develops beneath the jawline or along the side of the neck indicates the infection has spread beyond the immediate tooth area into the deeper fascial spaces of the head and neck.

In rare and serious cases, untreated dental infection can reach distant areas. Signs of brain infection from tooth sources are exceptionally uncommon but can include severe headache, confusion, and neck stiffness. Similarly, signs of heart infection from tooth bacteria — known as infective endocarditis — may present as unexplained fatigue, fever, and heart murmur changes.

These complications are rare. The purpose of mentioning them is not to cause alarm, but to reinforce the importance of treating dental infections before they have any chance to progress.

Signs of Infection After Tooth Extraction

Some discomfort, minor swelling, and slight oozing are perfectly normal during the first two to three days after having a tooth removed. However, there is a difference between normal healing and developing an infection.

Signs of infection after tooth extraction include:

• Increasing pain that worsens after the first 48 hours instead of improving
• Swelling that gets larger rather than smaller after day three
• Pus or a foul-tasting discharge from the extraction site
• A persistent bad taste in the mouth that does not go away with rinsing
• Fever developing several days after the procedure
• Throbbing or radiating pain that spreads to the ear or jaw

Signs of gum infection after tooth extraction can include red, inflamed tissue around the socket and tenderness when touching the area. If the gum tissue looks grey or the socket appears empty and dry, this may indicate dry socket rather than infection — though both need professional treatment.

A sign of tooth extraction infection that many patients overlook is worsening symptoms after initial improvement. If you felt better for a day or two and then symptoms returned, it may mean bacteria have entered the healing site.

Our guide on what to do after tooth extraction covers proper aftercare to reduce infection risk. If you suspect dry socket, read our article on dry socket prevention and treatment.

Can a Tooth Infection Spread to the Brain or Heart?

This is a question many patients ask, and it deserves an honest, balanced answer. Yes, in very rare cases, an untreated tooth infection can spread to distant parts of the body — including the brain and heart. However, this is uncommon and typically only occurs when infection has been left untreated for a prolonged period.

Signs of brain infection from tooth sources could include a persistent severe headache, neck stiffness, sensitivity to light, and confusion. A brain abscess caused by dental bacteria is a serious condition, but it is also extremely rare when infections are managed promptly.

Signs of heart infection from tooth bacteria relate to a condition called infective endocarditis. Bacteria from an oral infection can occasionally enter the bloodstream and attach to damaged heart valves. Symptoms may include unexplained fever, night sweats, fatigue, and new or changed heart murmurs.

The key message is simple: treating a dental infection early removes the risk of distant spread. Routine dental care and timely emergency treatment are your best protection.

For related reading, see our article on whether an infected tooth can cause sinus pain.

When Tooth Infection Becomes a Dental Emergency

Not every toothache is an emergency, but certain signs indicate you need to be seen urgently. Understanding when a tooth infection crosses from uncomfortable to potentially dangerous helps you make the right decision.

You should seek same-day emergency dental care if you experience:

• Rapidly increasing facial or neck swelling
• High fever (above 38°C) alongside dental pain
• Difficulty breathing or swallowing
• Feeling confused, dizzy, or very unwell
• A rapid heartbeat alongside signs of infection

These can be signs of sepsis from tooth infection or signs of blood infection from tooth bacteria entering the bloodstream. Sepsis is the body's extreme response to infection. It is treatable, especially when identified early.

If you recognise these symptoms, do not wait to see if they improve. Contact an emergency dentist immediately. We also accept walk-in patients for urgent dental concerns. You can book an emergency appointment online for the fastest response.

How Dentists Diagnose a Spreading Tooth Infection

When you visit an emergency dentist with a suspected infection, the assessment is thorough and methodical. Understanding what happens during diagnosis can help reduce any anxiety about the appointment.

The dentist will begin with a clinical examination. They will check for swelling, tenderness, and signs of pus around the affected tooth. They will test whether the tooth responds to temperature and pressure.

Dental X-rays are usually taken to identify the source of infection. An X-ray can reveal:

• Abscess formation at the root tip
• Bone loss around the infected tooth
• Deep decay reaching the nerve
• Signs of tooth infection after filling — such as decay beneath an existing restoration

By identifying the exact location and extent of the infection, the dentist can plan the most effective treatment. In some cases, a root canal treatment may be recommended to save the tooth while removing the infected tissue.

Treatment Options for Advanced Tooth Infection

Treatment depends on how far the infection has progressed. In most cases, the dentist will aim to eliminate the infection at its source and prevent further spread.

Common treatment approaches include:

• Incision and drainage — if an abscess has formed, the dentist may drain it to release trapped pus and reduce pressure
• Root canal treatment — this removes infected tissue from inside the tooth, cleans the root canals, and seals them to prevent reinfection
• Tooth extraction — if the tooth is too damaged to save, removing it eliminates the source of infection entirely
• Antibiotics — prescribed when the infection shows signs of spreading beyond the immediate area, to support the body in fighting bacteria
• Monitoring systemic symptoms — if there are any concerns about wider infection, the dentist will monitor your temperature, swelling, and general condition

For urgent pain and infection management, visit our severe toothache treatment page. Our private emergency dentist service offers same-day appointments with experienced clinicians.

How to Prevent Tooth Infection from Spreading

Prevention is always better than treatment. Taking a few simple steps can dramatically reduce your risk of developing a dental infection — and stop an existing problem from getting worse.

• Seek early treatment. If you notice any warning signs of tooth infection — pain, swelling, sensitivity — arrange a dental appointment promptly. Early intervention is the single most effective way to prevent complications.
• Maintain good oral hygiene. Brush twice daily with fluoride toothpaste, clean between teeth with floss or interdental brushes, and use an antiseptic mouthwash if recommended by your dentist.
• Attend regular check-ups. Routine dental examinations catch small problems before they become infections. Your dentist can identify early decay, cracks, or gum issues that could lead to infection if left untreated.
• Do not ignore warning signs. A toothache that comes and goes is still worth investigating. Intermittent pain can indicate a developing problem that will worsen without treatment.
• Follow aftercare instructions. After any dental procedure, follow the care guidelines provided by your dentist. Proper aftercare reduces the risk of post-treatment infection significantly.

For quick pain management tips while you arrange an appointment, read our guide on how to stop tooth pain fast.

Frequently Asked Questions

What are the signs of tooth infection?

Common signs of tooth infection include persistent throbbing pain, swelling around the tooth or gum, sensitivity to hot and cold temperatures, a bad taste in the mouth, and darkening of the affected tooth. You may also notice a small bump on the gum near the tooth root, which can indicate an abscess forming.

What are the signs of sepsis from tooth infection?

Signs of sepsis from tooth infection include a high fever, rapid heartbeat, rapid breathing, feeling confused or disorientated, and extreme fatigue or feeling very unwell. Sepsis is the body's serious response to infection entering the bloodstream. If you experience these symptoms alongside dental pain or swelling, seek urgent dental care immediately.

What are the signs of blood infection from tooth?

Signs of blood infection from tooth bacteria include a persistent high temperature, chills, a fast heartbeat, low energy, and general malaise. Blood infection — or bacteraemia — occurs when oral bacteria enter the bloodstream through an untreated abscess or severe gum disease. Prompt dental treatment prevents this from developing.

What are the signs of infection after tooth extraction?

Signs of infection after tooth extraction include increasing pain after the first 48 hours, swelling that worsens rather than improves, pus or discharge from the extraction site, a persistent bad taste, and fever. Normal post-extraction discomfort should gradually improve each day. If symptoms worsen, contact your dentist for assessment.

Can a tooth infection spread to the brain?

In very rare cases, an untreated tooth infection can spread to the brain, potentially causing a brain abscess. This is extremely uncommon and typically only occurs when a severe infection has been left without treatment for an extended period. Early dental care eliminates this risk entirely.

When should I see an emergency dentist?

You should see an emergency dentist if you have severe dental pain that does not respond to painkillers, rapidly increasing facial swelling, difficulty swallowing or breathing, a high fever alongside dental symptoms, or any signs of infection spreading beyond the tooth. Same-day appointments are available at Emergency Dentist London.