Which Itch Is Which?
Biting gnats, lice, ticks, fungus, and allergies can all cause itching. If your horse rubs bald spots in his mane or tail, check him thoroughly for external parasites such as lice or ticks, parasites (such as pinworms), or fungus, and treat according to your veterinarian’s instructions.
Itching can also be caused by ringworm, which is contagious to you and other horses. If a horse has ringworm, you will need not only to treat the horse but also to disinfect grooming tools, halters, blankets, stalls, feeders, and anything else he may have rubbed on.
Some horses (and dogs) seem to be hypersensitive or allergic to insect bites and once they are bitten, they go into a rubbing frenzy, which then invites other complications. In some cases, this is referred to as sweet itch or Queensland itch. A veterinarian should be consulted, but prevention of bites to susceptible animals is paramount. Remedies include soothing witch hazel or vinegar rinses, and possibly a corticosteroid prescription from your veterinarian.