Canker sores (aphthous ulcers) are small, painful lesions that develop on the soft tissues inside a child’s mouth, such as the inner cheeks, lips, or tongue. They typically appear round with a white or yellowish center and a distinct red border, making eating and talking uncomfortable. Canker sores are not contagious, distinguishing them from cold sores, which are viral and usually appear outside the mouth. While the exact cause remains unknown, these sores are common in children and teens, often healing on their own, but prompt action can provide significant pain relief.
Immediate Relief Using Household Items
Parents can provide immediate comfort using simple, non-medicinal items found at home. A saline rinse is an effective treatment that cleanses the area and helps reduce inflammation. To prepare it, dissolve half a teaspoon of salt in one cup of warm water. Have your child swish the solution for about 30 seconds before spitting it out. This method is only suitable for children who can reliably rinse and spit.
Baking soda (sodium bicarbonate) is another useful item that can help neutralize the acidic environment irritating the sore. Mixing a small amount of baking soda with water creates a paste that can be gently dabbed directly onto the ulcer using a clean cotton swab. For older children, a baking soda rinse can be prepared by dissolving one teaspoon of baking soda in half a cup of warm water. These alkaline solutions help soothe the sore and may promote faster healing.
Applying cold also offers temporary numbing relief by constricting blood vessels in the affected area. Allowing a child to slowly dissolve ice chips, a popsicle, or a small ice cube over the sore can significantly reduce pain and swelling. If the sore is accessible, a cold compress held against the cheek from the outside can also lessen discomfort. This application of cold is particularly helpful during the first few days, which are typically the most painful.
Over-the-Counter and Topical Medications
When household methods are insufficient, over-the-counter (OTC) products offer targeted pain management. Topical anesthetic gels and liquids can be applied directly to the sore to temporarily numb the area, allowing the child to eat and drink comfortably. These products often contain ingredients like benzocaine or lidocaine, which block nerve signals.
The FDA cautions against using benzocaine-containing products, especially for children under two years of age. This ingredient can cause methemoglobinemia, a rare but dangerous blood condition where oxygen carried in the blood is significantly reduced. Even in older children, these topical anesthetics should be used sparingly and exactly as directed to minimize systemic absorption.
Alternative OTC options include protective pastes and patches designed to cover the sore, shielding it from irritation. Products containing bismuth subsalicylate or antacids like milk of magnesia can coat the ulcer, providing a physical barrier and promoting a less acidic healing environment. To apply these treatments effectively, gently dry the area with a tissue or cotton swab before placing the medication directly on the sore.
Some specialized oral rinses contain mild antiseptics, such as hydrogen peroxide, which can cleanse the canker sore and prevent secondary infection. Avoid any mouthwashes or rinses that contain alcohol, as this causes a painful burning sensation and further irritates the ulcer. Highly acidic topical treatments or crushed aspirin should never be applied directly to the sore, as they damage the delicate oral tissue.
When to Consult a Pediatrician
While most canker sores resolve naturally, certain signs indicate a need for professional medical attention. A sore that persists for longer than two weeks without showing signs of healing should be examined by a healthcare provider, as this prolonged duration can suggest an underlying issue.
Sores that are unusually large (exceeding a quarter-inch) or appear in a large cluster (herpetiform ulcers) warrant a doctor’s visit. Prompt medical assessment is required if the canker sore is accompanied by systemic symptoms. These symptoms include a high fever, diarrhea, a rash, or swollen lymph nodes, which may indicate an associated condition needing specific diagnosis.
Difficulty swallowing or drinking due to pain is a significant red flag because it can lead to dehydration, especially in young children. If your child refuses liquids or shows signs of reduced urination, they should be seen immediately. A pediatrician can confirm the diagnosis and may prescribe stronger treatments, such as a specialized mouth rinse containing a steroid like dexamethasone or a topical prescription paste, if OTC options have failed.
Identifying and Limiting Canker Sore Triggers
Long-term management involves identifying and limiting exposure to common triggers. Dietary factors are frequent culprits, as highly acidic foods irritate the oral mucosa. When a child has an active sore or is prone to outbreaks, limit or avoid:
- Citrus fruits
- Tomatoes
- Pineapples
- Spicy or salty foods
Physical trauma to the mouth is another major trigger for ulcer development. This includes accidental cheek or lip biting, irritation from orthodontic braces, or aggressive tooth brushing. Parents should ensure their child uses a soft-bristled toothbrush to prevent micro-abrasions to the gums and inner cheeks.
Nutritional deficiencies have been linked to recurrent canker sores in some children. Low levels of B vitamins (folate and B12), iron, and zinc are associated with increased susceptibility. Addressing these deficiencies through dietary adjustments or supplements, often recommended by a pediatrician, is part of a comprehensive prevention strategy.
Parents can also manage the frequency of canker sores by switching to a toothpaste that does not contain sodium lauryl sulfate (SLS). SLS, a common foaming agent, can irritate the mouth lining in susceptible individuals, potentially triggering an ulcer. Keeping a log of when sores occur and what the child was eating or doing can help accurately identify personal triggers for better long-term management.