Cold sores occur usually about the lips or at the angles of the mouth, although they may appear anywhere on the face. Cold sore has a round, oval, or irregular outline, from the size of a pea to that of a quarter of a dollar, and is seen as a slightly raised patch on the skin on which is a group of very minute blisters, three to twelve in number. Cold sore may be single or multiple, and near together or widely separated on the face. Having first the appearance of a red patch, it later becomes covered with a brown crust from the drying of the contents of the tiny blisters. Cold sore often gives rise to burning, itching, or tingling, the disfigurement usually causing more annoyance, however, than the pain. The duration of the trouble is from four to twelve days.

Cold sores are commonly induced by indigestion and fevers, and also are occasioned by local irritation of any sort, as from nasal discharge accompanying cold in the head (from which the name is derived), by the irritation produced by a pipestem or cigar, and by rubbing the skin.

Treatment. Picking and scratching are very harmful, and cigar or pipe smoking must be stopped. Painting the sore with collodion, by means of a camel’s hair brush, is poor treatment in the early stages. Better use spirits of camphor, and afterwards, if there is much itching or burning, sopping the eruption with calamine lotion will relieve the discomfort.