The rainy season brings a number of problems. Everyone who owns a horse has heard of "mud fever" and "rain scald".

What is mud fever?
Mud fever, also known as greasy heel, is a condition found on the lower limbs of horses, usually in the area at the back of the pastern, just above the heels (hence the name "greasy heel").

Causes
A number of micro-organisms are involved as causative agents, and it often is not easy to clear the problem. Bacteria, such as Staphylococcus and Dermatophilus play a role, but so do fungi. Sometimes skin mites are involved as well.

Under normal conditions the skin protects the body against infections. The skin on the back of the pastern of horses, especially those ridden regularly, tends to pick up damage (often too small to see) due to contact with sand and soil, especially under wet conditions. This damage allows the micro-organisms to take hold.

What is rain scald?
Rain scald is a common skin infection seen in horses, and varies in appearance from small, matted tufts of hair to large crust-like scabs. The scabs are easily removed, exposing pink, pussy skin.

Cause
Rain scald is caused by Dermatophilus – one of the organisms that is also involved in mud fever. This organism can survive in quiescent form on normal, healthy skin. When the climate changes to warm and humid, biting insects are more prevalent. The damage done to the skin by these insects is sufficient for the organism to launch its attack.

Treatment
Management plays an important role in the prevention of both of the above conditions.
• If at all possible, rotate horses between paddocks under wet conditions, so that they do not have to stand in the mud.
• Clip long hair and remove all scabs (this could be painful, so be careful).
• Control biting insects and ticks.
• Wash the horse with antimicrobial shampoo (consult your veterinarian to find one that is effective against bacteria and fungi). Lather the horse, leave on for 10 minutes, rinse off, and dry off (remember, the organisms like wet conditions).
• Apply an antimicrobial ointment (once again, consult your veterinarian in this regard). Beware of home remedies, as these often cause additional damage to the skin and, although they might appear to be effective, they leave sufficient damage for the condition to flare up later).
• Immune-boosting drugs can be considered.
• Isolate affected horses. Use separate grooming equipment, feed and water buckets. Wash your hands with an antimicrobial hand wash after touching an affected horse.