The redness and itchiness at the edge of the tongue in children may be caused by allergies, mouth ulcers, papillitis of the tongue and other factors. 1. Allergy: consuming some allergy-prone substances, resulting in an allergic reaction on the edge of the tongue, will make the edge of the tongue red, itchy, and may be accompanied by mild tingling. 2. Mouth ulcers: may be related to infection, nutritional deficiency, heredity and other factors, in the early stage of the lesion, it will make the edge of the tongue red and itchy, and there will be localized superficial ulcers, and in severe cases, pain and swelling will occur. 3. Tongue papillitis: it may be caused by local irritation, infection and other factors, which will lead to localized redness and itching of the tongue, and may be accompanied by tongue pain, abnormal taste and other manifestations. The redness and itching on the edge of the tongue may be abnormal, so parents are advised to take their children to the doctor for examination and treatment.