Hand-foot-and-mouth disease is a mild viral illness that typically occurs in the spring and summer months, caused by Coxsackievirus A16. Children develop blisters in the mouth and/or palms and soles; these resolve after several days without treatment. View this nice photo of blisters on a palm. Hand-foot-and-mouth is not treated by an antibiotic, since it is a viral illness. Tylenol or ibuprofen can be taken for the fever, and fluids are very important. Hand-foot-and-mouth disease is quite different from, and totally unrelated to, foot-and-mouth, or hoof-and-mouth, disease.