Small children with blisters on the corners of the mouth rotting corners of the mouth to consider is keratitis, herpes simplex, saliva rash and so on. 1. Keratitis: this is an inflammatory disease of the corners of the mouth caused by infectious or non-infectious factors, more commonly microbial infections, when the body’s immune system is lowered or the local skin breaks down, bacteria, fungi and viruses that colonize the area around the corners of the mouth will enter the local area to appear infectious keratitis. 2. Herpes simplex: herpes simplex is an infectious disease caused by the herpes simplex virus, after the patient is infected with the virus, the virus will be latent in the body, when there is a low immunity, the virus will replicate, if it is herpes orofacialis, it usually occurs in the skin mucous membrane junction, such as the corners of the mouth and the edge of the lips. 3. Drooling rash: some relatively small children are prone to drooling, if not dried in time, the skin is often wet or friction, will cause damage to the skin cuticle, the appearance of drooling rash, but also blisters at the corners of the mouth, rotting corners of the mouth symptoms. Children with blisters on the corners of the mouth rotten corners of the mouth, should be for the cause of the symptomatic treatment, usually pay attention to maintain local cleanliness and hygiene.