This is a disease due to a microscopical vegetable fungus, which, commencing to grow in the hair follicles or roots, destroys the hairs, and makes bare circular patches of varying size, with scales or scurf upon them. There is but little itching, though the inflammation set up may cause soreness. The disease is very contagious and disfiguring, and, if not treated in time, may be very intractable. Young horses are more susceptible to it than old ones. Before the bare patches appear, when the hand is passed over the skin, little rough spots can be felt, and the hair can be seen to stand erect over these.
If there are only isolated patches, these may be treated by rubbing in a little Stockholm tar or iodine ointment; if the disease be more diffused over the skin, then the treatment as for mange should be adopted.