My 3-year-old son currently in pre-school has developed patches/wounds in her mouth. Could this in any way be a contagious condition from his peers or it is caused by something else? How do I treat it? Karenzi Dear Karenzi, Since how long is your child having these patches/wounds in her mouth? Are they painful causing difficulty in speaking/eating and or drinking or she is comfortable with it? Canker sores is the most common cause for 1 or 2 wounds inside the mouth in a small child. They most commonly occur due to minor injury like eating hard food, tongue bite while eating, e.t.c. They can be due to vitamin deficiency or food allergy as well. The canker sore is a small painful ulcer with white center and red border. It is one or 2 in number only, located inside lips or cheeks. Though painful, it is not contagious. Hand, foot and mouth disease can cause sores in mouth of children, which commonly occur over tongue and sides of mouth. There may be associated deep blisters in hands and feet. It is due to viral infection (Coxsackie virus is commonly implicated, but some enteroviruses can also cause it). It is common in children between 1 to 5 years of age and is contagious mostly during the first week of sickness. Adults if suffering from cold can transmit infection to small children, with sores and blisters around mouth as one of the manifestations. Herpes simplex, herpes labialis are viral infections which can cause multiple small eruptions around mouth or inside mouth in small children. Children with reduced immunity like those suffering from HIV/AIDS, malnutrition, e.t.c. can develop fungal infection inside the mouth which would manifest as red, white or black patches, with difficulty in swallowing/speaking. Prevention lies in keeping good hand and mouth hygiene of self as well as of the child. Many infections like herpes, canker sores, e.t.c. are transmitted to children from adults as while kissing. Discourage kissing a child for show of affection. Keep anyone having a running nose or symptoms of cold, away from a small child, because this can transmit viruses which can cause sores, wounds around and inside mouth of a small child. Treatment depends on treating the underlying cause. However many home remedies have been known to be soothing in case of mouth ulcers and actually help to heal them. Applying honey in small quantity is useful. Similarly using turmeric paste, juice of aloe vera, coconut water, e.t.c. is also beneficial. Lukewarm water with salt has also been known to be soothing.