InformationQuestion:What causes fever blisters?Answer:A fever blister located on the lips, mouth, and face is usually caused by the highly contagious herpes simplex type 1virus. Only a small number are caused by herpes simplex type 2, the type usually associated with genital lesions.There is no cure for a fever blister. However, there are medications that will relieve the pain and itchiness, and speed the healing of the blister.See: Herpes labialis (oral herpes simplex)ReferencesWhitley RJ. Herpes simplex virus infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 397.