Rain Rot Equine Skin Disease

Rain rot, scientifically called equine dermatophilosis, is a contagious skin infection that affects the skin of the back, flanks, and hindquarters. It is caused by the bacteria Dermatophilus congolensis, which enters the hair follicles. The condition is activated by moisture, such as when the horse is kept in very wet pastures.

  1. Diagnosis

    • If the bacteria, Dermatophilus congolensis, appears on the smears from the underside of a scab or crust during examination, then the diagnosis is positive.

    Symptoms

    • The skin along the horse's back and on each side of the neck develops scabby, crusty lesions. Under the crusts, the skin is moist, filled with pus, red and inflamed. Due to the damage to the hair follicles, the entire hair shaft will pull out easily, leaving bald spots. The extreme irritation makes the horse very uncomfortable and the decline in his body condition is apparent.

    Cause

    • Dermatophilus congolensis is the primary organism associated with rain rot, although other bacteria can become secondary contaminants. Constant rain washes out the protective skin oils, softens the horse's skin and allows the organism a chance to invade the skin.

    Treatment

    • Treatment of rain rot when discovered early requires the horse's skin to be dried and gently groomed to stimulate the body's natural defense mechanism. However, if neglected, the condition requires treatment more rigorous treatment. Clip away the hair surrounding the crusts and shampoo the skin with a medicated wash, such as Betadine or Chlorhexidine to remove the crusts. The uncovered sores will require an antibiotic ointment: penicillin, amoxicillin and erythromycin. Repeat this procedure until all affected areas have been treated.

    Secondary Problems

    • Do not leave horses outside who have lost a great deal of hair due to rain rot. They can easily suffer severe sunburn. Applying a sunscreen only adds to the problem since sunscreens contain moisture, which feeds the bacteria. When the horse is outside, cover him with a horse blanket and fly mask.