Causes Of Canker Sores In Children, Its Symptoms And Treatment

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Canker sores in kids can be painful as they interfere with drinking and eating. These tiny, noncontagious lesions on the oral mucosal layer are also called aphthous ulcers or mouth ulcers. Most canker sores resolve on their own within one or two weeks (1). These may occur at any age but are more often seen in children and adolescents (2). Rinsing the mouth may help reduce the symptoms. However, it is recommended to consult a doctor and treat the underlying cause if your child keeps having canker sores. Continue reading to know more about canker sores’ causes, symptoms, treatment, and prevention and how to differentiate them from cold sores.

Causes Of Canker Sores In Children

The exact cause is not clear in most cases. Hereditary and environmental factors, such as certain food or allergens, can cause recurrent canker sores.

The possible causes of canker sores in children may include the following (3) (4).

  • Dietary deficiency of iron, folate (folic acid or vitamin B9), cobalamin (vitamin B12), or zinc
  • Accidental cheek bite
  • Mucosal damage from incorrect brushing of teeth
  • Injuries due to orthodontic braces
  • Food allergies or sensitivities, commonly to coffee, nuts, eggs, chocolates, and fruits, such as citrus fruits and strawberries
  • Emotional stress
  • Constipation can be a possible reason.

The following diseases and conditions can also be the reason for canker sores (5).

  • Autoimmune conditions, such as celiac disease, inflammatory bowel diseases (ulcerative colitis and Crohn’s disease), and Behcet’s disease
  • Infection from certain pathogens, such as the Helicobacter pylori, and immunocompromised conditions, such as HIV/AIDS

Note: Canker sores are not seen in herpes virus infection, which may cause cold sores in the mouth and lips.

Signs And Symptoms Of Canker Sores In Children

Pain is the primary symptom of canker sores. The child may have a burning or tingling sensation associated with the sores. Sometimes, burning can be felt before the lesions appear on the oral mucosal layer (3).

Canker sores are round or oval-shaped lesions with yellow or white-colored center surrounded by red borders. They are seen under the tongue, inside the cheek, on the soft palate, or the gums.

Is It A Canker Sore Or A Cold Sore?

Cold sores or fever blisters can occur in clusters of many sores. These may merge to form large ulcers and lack proper borders and shapes. Cold sores are often seen on the lips, unlike canker sores, which mostly occur on the oral mucosal layer.

Cold sores due to herpes simplex virus type 1 are common among kids. These sores last for three weeks and heal without scarring. Fever, itching, sore throat, and swollen lymph nodes are often associated with herpetic cold sores (6).

Should Parents Worry About Canker Sores?

Occasional canker sores that heal within a week or two are not significant causes of concern in children.

Seek pediatric consultation in the following situations.

  • Mouth sores lasting more than two weeks
  • Recurrent or frequent canker sores
  • Large canker sores
  • Excessive pain
  • Sores present on lips
  • High fever and a feeling of sickness
  • Sores interfere with eating and drinking

If you are unable to differentiate canker sores from cold sores, ask your child to avoid touching sores and teach them hand hygiene techniques since cold sores are contagious. Consult a pediatrician to determine the type of sores.

How Are Canker Sores Diagnosed?

Doctors can identify canker sores by visual inspection (3). If your child has severe and frequent sores, additional examinations are conducted to identify the underlying cause. Healthcare providers will choose the required tests based on other symptoms and individual factors.

If the canker sores are due to injuries caused by misaligned teeth or dental appliances, then the pediatrician may refer the child to a dentist.

Treatment For Canker Sores In Children

Minor canker sores are cured within a week or two without any treatment. Large sores may require medical care, which can include the following (7).

  • Pain-relieving over-the-counter topical products such as creams, gels, mouthwash, or pastes could help minor sores. Topical products with active ingredients, such as benzocaine, fluocinonide, or hydrogen peroxide, may enhance healing.
  • Mouth rinses containing corticosteroids are prescribed by a doctor to reduce pain and inflammation if multiple or more extensive sores are present.
  • Vitamin and mineral supplementations are often prescribed if dietary deficiencies are the cause for canker sores.
  • Oral medications such as Carafate (sucralfate) or colchicine are used to treat severe canker sores.
  • Oral steroid medications are often given to control severe inflammation.
  • Chemical or instrumental cautery is required for severe cases of canker sores.

Seek a pediatrician’s help to choose the best method to cure canker sores in your child. Treatment may vary if any underlying disease or condition is detected. The sores may heal by themselves during the treatment of the underlying condition.

Home Remedies For Canker Sores

The following home care measures and lifestyle changes may help heal canker sores in children.

  • Apply ice to reduce pain and swelling
  • Avoid acidic, hot, and spicy food that may increase pain
  • Rinse mouth with saltwater or baking soda rinse
  • Use a soft toothbrush with sodium lauryl free toothpaste
  • Eat soft and non-abrasive foods to avoid pain

Prevention Of Canker Sore In Children

The following tips may help reduce the risk of canker sore in children (8).

  • Follow a balanced diet that included mixed nutrients
  • Follow healthy oral hygiene habits
  • Seek dental care for misaligned teeth and follow dentist recommendations while using dental appliances
  • Avoid foods that cause allergies

You may also give your kid vitamin and mineral supplements if it is recommended by the pediatrician.

Canker sores in kids are lesions in the oral mucosa that are usually not a significant cause of concern. However, they may cause pain during eating and drinking. Nutritional deficiencies, food allergies, or cheek bites may cause canker sores, which resolve in about a week or two. Speak to a doctor if the sores persist longer or become painful. The doctor may prescribe topical gels, mouthwashes, dietary supplements, dietary changes, or medications. Proper oral hygiene and a balanced diet may help prevent canker sores in children.

Infographic: Common Reasons For Mouth Ulcers In Children

Children may experience sores and mouth ulcers due to several other diseases, which usually present other notable symptoms. See the infographic below to understand better the various conditions that can cause mouth ulcers in children.

conditions that cause mouth ulcers in children [infographic]
Illustration: MomJunction Design Team


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Canker sore; MedlinePlus; The United States National Library of Medicine
2. Canker Sores (Aphthous Ulcers) in Children; Cedars-Sinai Medical Center
3. Canker sores (mouth ulcers): Overview; The United States National Library of Medicine
4. Zinc; University of Rochester
5. Mohamed Nasser Elsheikh and Magdy ElSayed Mahfouz, Prevalence of Helicobacter pylori DNA in Recurrent Aphthous Ulcerations in Mucosa-Associated Lymphoid Tissues of the Pharynx; JAMA Otolaryngology-Head & Neck Surgery
6. Herpes – oral; MedlinePlus; The United States National Library of Medicine
7. Canker sores (mouth ulcers): What can you do if you have a canker sore?; The United States National Library of Medicine
8. Mouth ulcers; Betterhealth; The Victoria State Government


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Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more

Dr. Garima Garg Seth

Dr. Garima Garg Seth is a well-known pediatrician in Gurgaon, having more than 19 years of experience in this field. She has completed her education from topmost organizations in India, including AIIMS, New Delhi; Sir Ganga Ram Hospital, New Delhi; and CMC Vellore. She headed the pediatric ICU of Max Hospital Gurgaon for six years.  Dr. Seth is a strong... more