5 Ways The Flu and Sinus Pressure Can Cause Tooth Pain

When most people think of the flu, symptoms like fever, body aches, fatigue, and congestion immediately come to mind. However, tooth pain is a lesser-known and often surprising symptom some individuals experience during a bout of influenza. While this may seem unrelated at first, there are several ways in which the flu can indirectly contribute to dental discomfort.

1) Sinus Pressure and Inflammation

Sinus congestion is among the most common causes of tooth pain during the flu. The maxillary sinuses, located just above the upper teeth, often become inflamed or blocked during upper respiratory infections like the flu. This can result in increased pressure on the roots of the upper molars, leading to a dull, aching pain that mimics a toothache.

Because the roots of the upper teeth are located so close to the sinuses, the inflammation and pressure caused by sinus congestion can be mistakenly interpreted as dental pain. This condition, known as referred pain, usually affects several teeth and can often be relieved once the sinus infection resolves.

What is Sinusitis?

Sinusitis is the inflammation or swelling of the tissue lining the sinuses, which are the air-filled cavities in the bones around the nose and eyes. It typically occurs when the sinuses become blocked due to an infection, allergy, cold, or nasal polyps, preventing proper drainage and causing mucus buildup.

Common symptoms of sinusitis include:

• Nasal congestion or blockage
• Thick nasal discharge (often yellow or green)
• Facial pressure or pain, especially around the cheeks, eyes, or forehead
• Headache
• Reduced or lost sense of smell or taste
• Tooth or upper jaw pain
• Fever (in some cases)

There are different types of sinusitis, including:

• Acute sinusitis: usually lasts less than 4 weeks and is often caused by a viral infection.
• Subacute sinusitis: lasts 4 to 12 weeks.
• Chronic sinusitis: lasts more than 12 weeks and may be due to long-term inflammation.
• Recurrent sinusitis: multiple episodes throughout the year.

Treatment varies depending on the cause but may include nasal sprays, decongestants, antibiotics (for bacterial cases), saline rinses, or surgery in some chronic cases.

When you have the flu, the viral infection can lead to inflammation and swelling in the nasal passages and sinuses. This inflammation can block normal sinus drainage, creating an environment where bacteria or additional viruses can grow.

Secondary sinus infections (sinusitis) may occur if the sinuses remain blocked.

There are two main ways this can happen:

1. Viral Sinusitis: The flu virus can cause temporary inflammation of the sinuses, leading to symptoms similar to sinusitis (pressure, congestion, tooth pain), which often resolve independently.
2. Bacterial Sinusitis: In some cases, the blockage caused by the flu can lead to a bacterial infection in the sinuses, resulting in more prolonged or severe sinusitis that may require antibiotics.

So while sinusitis doesn’t always follow the flu, the flu can trigger or worsen sinus issues, especially in people prone to allergies, colds, or respiratory infections.

2) Bruxism and Jaw Tension

During periods of illness or stress, people are more likely to clench or grind their teeth—a condition known as bruxism. This may occur while sleeping or even subconsciously during the day.

When your body is under physical stress, such as fighting off the flu, the muscles around the jaw can become tense, which may worsen grinding tendencies.

This added tension can cause tooth sensitivity, jaw soreness, and pain radiating through the face, temples, or ears. If you notice a sore jaw or teeth that feel tender or worn down during the flu, bruxism may be the culprit.

3) Dehydration and Dry Mouth

Fever, sweating, vomiting, and decreased fluid intake—all common with the flu—can lead to dehydration. Dehydration often causes dry mouth (xerostomia), which reduces saliva flow. Saliva plays a vital role in maintaining oral health by neutralising acids, washing away food particles, and helping to prevent tooth decay.

Without adequate saliva, bacteria and plaque can accumulate more rapidly, increasing the risk of tooth sensitivity, decay, and gum irritation. This can make already vulnerable areas of the mouth more prone to discomfort or pain during illness.

4) Weakened Immune System and Pre-Existing Conditions

When your immune system is compromised during the flu, it can exacerbate underlying dental issues such as gingivitis, tooth decay, or periodontal disease. Inflammation may increase, making the gums more sensitive or causing previously dental-manageable problems to flare up.

In some cases, a minor dental infection your body was previously managing may become more painful or inflamed during the flu, highlighting the importance of addressing oral health concerns before illness strikes.

5) Mouth Breathing and Sensitivity

Nasal congestion caused by the flu often forces individuals to breathe through their mouths, especially during sleep. Mouth breathing can dry out oral tissues, contribute to tooth sensitivity, and increase the risk of enamel erosion and gum irritation.

Prolonged mouth breathing can lead to discomfort in the teeth and gums, especially when combined with dehydration.

When to See a Dentist

Tooth pain during the flu may subside once your other symptoms improve. However, if the pain persists, worsens, or is localised to a single tooth, it’s essential to consult a dentist.

Persistent dental pain could indicate a problem that requires professional attention, such as a cavity, a cracked tooth, an abscess, or gum disease.

Prompt dental care alleviates pain and prevents minor issues from becoming more serious health concerns, especially when your immune system is already compromised.

Maintaining Oral Health During the Flu

To minimise the risk of tooth pain while recovering from the flu, consider the following tips:

• Stay hydrated to keep your mouth moist and support your immune system.
• Use a saline nasal spray or steam inhalation to reduce sinus pressure.
• Maintain good oral hygiene, even when feeling unwell.
• Use a soft-bristled toothbrush if your gums feel sensitive.
• Rinse your mouth after vomiting to protect your enamel from stomach acid.
• Avoid sugary cough drops and acidic beverages that can irritate the teeth.
• Consider wearing a night guard if you’re prone to grinding or clenching your teeth.

Don’t Overlook Sinus-Related Tooth Pain During the Flu

While the flu primarily affects the respiratory system, its impact on oral health, particularly tooth pain, shouldn’t be overlooked. Several factors can link influenza to dental discomfort, from sinus pressure and bruxism to dehydration and underlying dental conditions.

By staying mindful of your oral health and seeking timely care, you can prevent flu-related tooth pain from becoming a bigger problem.

Contact your local Amazing Smiles dental clinic for a professional evaluation if you’re experiencing persistent tooth pain during or after the flu. Our caring team is here to help restore your smile and comfort with expert care and personalised attention.