Ringworm

Ringworm is a common contagious skin disease of horses. It is caused by a fungal infection. It is important to note that humans can become infected by handling infected horses and contaminated tack. Infection is transmitted among horses by direct contact with an infected animal (including humans) or by indirect contact via contaminated tack, covers, or fungal spores within the environment. Illness, poor nutrition, overcrowding, age and stressful environments predispose horses to infection. Young and elderly horses are more susceptible to infection. Continuous wetting of the horse’s skin e.g. sweating, washing-down can decrease the skin’s protective barrier therefore enabling infection to occur.

The classic ringworm lesion is a circular patch of hair loss with stubbly hairs on the margin. The skin can appear to be crusted and/or scaly. Ringworm lesions usually begin as small raised lumps that progress to the typical ringworm lesion. Some horses can become itchy and may also show evidence of pain.

Ringworm is usually a self-limiting disease and most horses recover within 1-6 months. Treatment is usually advisable as it decreases the transmission of disease between horses and other animals including humans. Antifungal shampoos are useful for decreasing the transmission of disease but do not alter the course of infection. Systemic treatment with antifungal drugs is effective but this is very expensive and it’s use is usually limited to humans and small animals e.g. dogs and cats.