what can cause a mouth infection or lesion - savina dental clinics malta and gozo

Any part of your body, including your mouth, is susceptible to infection or lesions (not all lesions are infections). Oral infections include gum disease & tooth decay, but may also be caused by viruses, bacteria and fungi as well as other conditions in children and adults alike. That is why you need to make sure that your oral infections are treated promptly to avoid the development of other dangerous conditions.

With proper oral hygiene, some of these infections can be prevented with most of them only lasting a few days, particularly those common in children. Still, there are other dental conditions that are more severe and are likely to stick around for longer if not treated. In this post, we will be looking at what can cause a mouth infection and the symptoms to look out for.

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What is mouth infection and how does it look like?

A mouth infection is a sore that is commonly caused by viruses and bacteria and fungi. It may appear as an individual painful ulcer or a red swelling on your mouth’s lining. Most ulcers are red, but some may be white due to the dead cells and the food debris stuck in the hollow part. Some sores are filled with fluids and look like blisters.

Different types of mouth infection and their causes:

Recurrent Aphthous Stomatitis (Aphthous ulcers, canker sores)

These are painful, but benign lesions that form on the gum, tongue, lips, palate and other mouth tissues. This condition is most common in children and adolescents. Its cause is not quite clear. However, stress, immune problems, hormones, food hypersensitivity and any related infections may trigger the development of canker sores. They take anywhere from 10 to 14 days to heal.

Related Article: How To Treat Recurrent Oral Ulcerations

Viral Infections

According to research by the Johns Hopkins Medicine, 50 to 80% of all adults in the US carry oral herpes, which is as a result of the herpes simplex virus. Oral herpes may cause blisters and ulcers on the tongue, or gum, flu-like symptoms or no symptoms at all. Once you are infected, the virus permanently resides in your body. However, with proper care, the infection can stay dormant. Recurring outbreaks of oral herpes are usually mild and can last anywhere from 7 to 10 days. Fluid-filled blisters will appear around your mouth, and after a day or two, they will rupture and form painless scabs.

Children aged between one and three that carry the simplex virus may sometimes develop a condition called herpes gingivostomatitis, which causes the gums to swell, revealing small blisters on their own. The child may also run a fever, become tired and irritable more easily. Once these symptoms disappear, the virus stays dormant in their body. But, exposure to sunlight, trauma, and stress may cause it to flare up.

Dental Caries

Popularly known as cavities and tooth decay, dental caries is a common oral infection. It is also the primary cause of tooth decay and loss of teeth in children aged 12 years and below. Dental caries is caused by bacteria known as Streptococcus mutans. This bacteria changes food, especially starchy and sweet foods into acid, which tends to eat away at the enamel of your teeth. Some of the symptoms of dental caries include sensitivity or pain in the affected tooth, especially when eating, hot, cold or sweet foods.

Recommended Reading: 8 Benefits Of A Regular Dental Check Up


Gingivitis is caused by multiple bacteria that settle along the gum crevices and produce toxins. These toxins irritate and inflame your gums, making them tender, red and swollen, and prone to bleeding whenever you brush or floss your teeth. If not treated, it may cause periodontal disease. Also, if some of these bacteria are inhaled into the lungs, they may cause pneumonia.

Periodontal Disease

When gingivitis is left untreated, it spreads below the gum line and affects the bone and all the supporting tooth tissues resulting in periodontal disease. Pockets form around your teeth, causing bone loss and inflammation. This will eventually result in tooth mobility (loosening) due to the ongoing bone destruction. Periodontal disease has also been linked to diabetes and heart disease.

Related Article: Receding Gums: What’s The Cause & How To Treat It

Hand, Foot and Mouth Disease

According to the University of Chicago, this condition is more common in babies and school-aged children, and it is caused by the Coxsackie A16 virus. The hand, foot, and mouth disease is characterised by symptoms like fever and sore throat which are often followed by painful blisters which tend to appear in the inner part of the cheeks and tongues, soles, buttocks, and palms. Fortunately, this infection often clears within three days.


Herpangina is linked to hand, foot and mouth disease. It commonly affects children aged between 3 and ten years during summer and fall seasons. It is marked by painful whitish sores with a red border that appear on the roof of your mouth. The first symptoms you will notice include a sore throat, difficulty swallowing and fever. These signs are followed by small blisters on the back of your mouth, forming large ulcers once they rupture. Herpangina infections typically last 3 to 5 days.

Oral Thrush

When the Candida Albicans, a naturally occurring fungus, starts to overgrow, it causes thrush. Thrush may also be as a result of a weakened immune system. Your immune system may become weakened by medical treatments like chemotherapy, radiation, and antibiotics, which destroy or kill your healthy cells that naturally prevent infection. This condition causes white, curd-like sores that appear on the inner cheeks, palates, back of the mouth and on the tongue. It can also cause cracks at the corners of your mouth. Thrush is a common infection amongst people with HIV and cancer due to weakened immune systems

Injury or Irritation from Food or Chemicals

Injury to your mouth can cause blisters or ulcers to develop in your mouth. Some foods and chemicals may also be irritating, triggering an allergic reaction that may cause mouth sores. These foods include astringents, cinnamon flavouring or acidic foods. Specific ingredients found in mouthwash, toothpaste, chewing gum, and candy may also irritate your mouth.

Tobacco Use

Smoking tobacco destroys your body’s infection-fighting bacteria, making it harder to ward off gum infection. The presence of these three bacteria; Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans are available in higher amounts in tobacco smokers. These bacteria are more likely to cause gum disease.

Savina Dental clinics Malta and Gozo what can cause an infection in the mouth


The most common type of drugs that cause mouth sores includes various cancer chemotherapy drugs. The same applies to medicines that contain gold, which is commonly used for treating rheumatoid arthritis among other autoimmune disorders may cause mouth sores. Fortunately, most of these medications are rarely used due to the development of safer and more effective drugs. Radiation therapy is another common cause of oral infections.

Systemic disorders

Many conditions that affect your oral health also affect other parts of your body. Some of these conditions include Stevens-Johnson Syndrome, which causes skin eruptions and mouth sores. Inflammatory bowel disease may also cause mouth sores. Nutritional diseases of vitamin B and C or iron may cause mouth sores.

Warning Signs

The warning signs of a mouth infection include;

  • Pain and fever
  • Gum inflammation and swelling
  • Swollen jaws
  • Swollen neck glands
  • Eye inflammation
  • Blisters on your skin

What a dentist can do

Although not all mouth infections need immediate evaluation, the information provided above can help you evaluate whether to seek medical help or not. You need to see your dentist if you experience the warning signs highlighted above. Your dentist will ask you questions about your symptoms as well as your medical history. They will inquire about your consumption of food, drugs and any other substances that may cause mouth sores. They can then perform a physical examination to check the location and the nature of your sores and a general examination of systemic disorders, which may be affecting your mouth. They may also need to run tests to confirm the cause of your mouth infection. The nature of the tests done will depend on what the medical professional has found during the history and physical examination.

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Savina Clinic – Dental & Implantology Centres are friendly, state-of-the-art practices in Malta and Gozo dedicated to comprehensive quality dental care. Savina Dental is an innovative dental practice in Malta and prides itself on the high-quality customer service, low waiting room times, attention to detail and the advanced dental technology at their disposal.

Joseph Xuereb
Principal Dental Surgeon & Owner of Savina Dental Clinics, Dr Joseph Xuereb BChD (Hons), MFGDP(UK), MGDS RCS(Eng), FFGDP RCS(UK), FICD is a general dental practitioner with a special interest in Implant and Restorative Dentistry. Dr Joseph & the teams' full biographical information can be found here.