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Updated on December 12, 2022
6 min read

Mouth Sores & COVID-19

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Overview: COVID-19 & its Symptoms 

Coronavirus, otherwise known as COVID-19, is an infectious disease caused by the novel coronavirus. Most people with COVID-19 will experience mild to moderate respiratory illness and recover without needing special treatment or hospital admission.

Older people and those with underlying medical issues such as cardiovascular disease, diabetes, chronic respiratory disease, and cancer are more likely to develop severe illness.

The best way to prevent and reduce transmission is to be well informed about COVID-19 and how it spreads. Wash your hands or use an alcohol-based rub frequently and avoid touching your face so you can protect yourself and others from infection.

COVID-19 spreads predominantly through droplets of saliva or discharge from the nose when an infected person coughs or sneezes. You must practice respiratory etiquette to avoid spreading the virus, such as coughing into a flexed elbow, if necessary.

The most common symptoms of COVID-19 are: 1

  • Fever
  • Dry cough
  • Tiredness or fatigue

Less common symptoms of COVID-19 are: 

  • Aches and pains
  • Sore throat
  • Diarrhea
  • Conjunctivitis (pink eye)
  • Headache
  • Loss of taste or smell
  • Skin rashes
  • Discoloration of the fingers or toes

Serious symptoms of COVID-19 include: 

  • Difficulty breathing or shortness of breath
  • Chest pain or pressure
  • Loss of speech or movement

If you have severe symptoms of coronavirus disease, seek medical attention immediately. Always call before going to your doctor or health facility. People with mild symptoms who are otherwise healthy should stay at home to manage their symptoms.

On average, it takes between five to six days from when someone is infected with COVID-19 for symptoms to show. However, it can take up to 14 days.

What are Some Uncommon Symptoms of COVID-19?

COVID-19 can also cause symptoms you may not expect, including: 2

Gastrointestinal Symptoms

COVID-19 may lead to nausea, vomiting, or diarrhea alone or along with other COVID-19 symptoms. Gastrointestinal symptoms may develop before fever and respiratory symptoms.

Skin Changes

The most common skin change related to mild to severe COVID-19 includes a flat, red rash covered with small bumps and discolored areas on the fingers and toes, otherwise known as COVID toes. COVID toes are more common in children and young adults. Discoloration or swelling can occur on one or several toes or fingers.

Blisters, rough skin, itchiness, pain, or painful raised bumps can develop. A small amount of pus may develop under the skin. These symptoms can last 10 to 14 days. However, in some reported cases, they persist for months.

It is essential to know that swollen, discolored fingers or toes could also be chilblains. This is an inflammatory skin condition. Chilblains occur in response to repeated exposure to cold air.

Hives is another skin change linked with developing COVID-19. 


Severe confusion, otherwise known as delirium, may be the primary or only symptom of COVID-19 in older people. This symptom is related to a high risk for poor outcomes, including death.

Eye Problems

Pink eye, otherwise known as conjunctivitis, may be a symptom of COVID-19. The most common eye problems linked to COVID-19 are light sensitivity and sore or itchy eyes.

Connection Between COVID-19 and Oral Health

COVID-19 has led to the closure and reduced hours of dental practices around the world, excluding emergency and urgent services. This limits routine care and prevention from health care providers.3

Dental care includes aerosol-generating procedures that increase viral infections of COVID-19. The pandemic provides an opportunity for the dental industry to move toward non-aerosolizing, prevention-centric approaches to treatment and away from surgical interventions.

Reports have emerged claiming COVID-19 may have oral health effects since the virus is affecting vasculature and disrupting blood flow. Studies are still being done to confirm if COVID-19 is causing tooth loss or bone loss. 

Additionally, research has shown that mouth sores may be a symptom of COVID-19.

Are Mouth Sores a Symptom of COVID-19? 

Mouth ulcers and sores are prevalent on the mouth, including on the tongue and lips. Many illnesses and infections can lead to changes in the tongue's surface, including an unexplained condition known as ‘geographic tongue’ that can persist for months.

In September of 2020, researchers in Spain reported that around a quarter of patients in hospitals with COVID-19 experienced oral manifestations to their mouth or tongue.4

While this study of 666 patients was small and considered preliminary, health care providers may consider adding oral lesions to the list of symptoms linked to COVID-19.

How Common are Mouth Sores With COVID-19?

It is unknown whether oral manifestations are common in mild COVID-19 cases. We do not yet know how common COVID-19 oral lesions are in the wider community of patients or how reliable they are as a symptom of COVID-19.

Who is at Risk of Developing Oral Lesions From Coronavirus?

Populations more susceptible to chronic illnesses are usually at higher risk of developing oral diseases from COVID-19 infection.

Common risk factors of developing oral manifestations from coronavirus include: 3

  • Stress
  • Poor diet
  • Alcohol and tobacco use
  • Substance misuse
  • Behavioral health problems
  • Domestic violence
  • Poverty

Many of these risk factors have developed or heightened during the COVID-19 infection pandemic. These and other social determinants of health result in both exacerbation of chronic disease and poor oral health outcomes.

How to Treat Mouth Sores 

Treatment is usually not required for minor oral cold sores. They tend to clear on their own in a week or two. 

However, large, persistent, or unusually painful mouth ulcers or sores may require medical care. Several treatment options are available, such as the options below.5

If you are unsure how to treat an oral lesion, speak with your health care provider for a diagnosis. They can provide medical advice.

Mouth Rinses

If you have several oral lesions, your doctor may prescribe a mouth rinse or wash containing the steroid dexamethasone to reduce pain and inflammation. Or, it may contain lidocaine to lessen pain.

Topical Products

Over-the-counter and prescription items may help reduce pain and speed healing if applied to individual mouth sores as soon as they appear.

These topical products include:

  • Pastes
  • Creams
  • Gels
  • Liquids and other fluids
  • Lozenges 

Some topical products contain active ingredients including:

  • Benzocaine (Anbesol, Kank-A, Orabase, Zilactin-B) 
  • Fluocinonide (Lidex, Vanos) 
  • Hydrogen peroxide (Orajel Antiseptic Mouth Sore Rinse, Peroxyl) 

There are many topical products for oral lesions, including those without active ingredients. Contact your doctor, dentist, or health care provider for advice and more information on which may work best for you.

Oral Medications

Oral medications may be used when oral lesions are severe or do not heal from topical products.

Oral medications may include:

  • Medications not intended specifically for mouth or cold sore treatment, including the intestinal ulcer treatment sucralfate used as a coating agent and colchicine, which is typically used to treat gout. 
  • Oral steroid medications when severe canker sores do not respond to other treatments. However, because of serious side effects, they are typically a last resort.
Last updated on December 12, 2022
6 Sources Cited
Last updated on December 12, 2022
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Coronavirus, World Health Organization (WHO)
  2. Unusual coronavirus (COVID-19) symptoms: What are they?, Mayo Clinic, March 2021
  3. Brian Z, Weintraub JA. Oral Health and COVID-19: Increasing the Need for Prevention and Access.  [Erratum appears in Prev Chronic Dis 2020;17.
  4. Nuno-Gonzalez, A et al. “Prevalence of mucocutaneous manifestations in 666 patients with COVID-19 in a field hospital in Spain: oral and palmoplantar findings.” The British journal of dermatology vol. 184,1 : 184-185
  5. Canker sore, Mayo Clinic, April 2018
  6. Fidan, Vural et al. “Oral lesions in Covid 19 positive patients.” American journal of otolaryngology vol. 42,3
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