Dermatophilosis, also known as mycotic dermatitis, rain scald, mud fever, and greesy heel, is a skin disease caused by fungal organism Dermatophilus congolensis which gains entry to the horse skin when it is saturated by prolonged rain. It is mainly seen in mild wet winters. Lesions are seen on the back, belly and lower limbs. Horses in poor condition and badly cared for at pastures are at risk. Horses with shaggy coats or with feather are particularly at risk.
Diagnosis is based on the appearance of the sores and microscopic examination of the organisms. Dry conditions and improved hygiene should be the first step in therapy. Affected animals must be housed. Long hair shielding the sores must be removed by clipping (sterilizing the blades after use). Astringent lotions are beneficial and antibiotics may be given when the sores are severe. Cracking of the skin may require prolonged careful treatment. Remove long hair and wash with mild soap and tepid water. Areas must be kept dry after initial washing. Dressing with antibiotic ointments is helpful. Rest in a dry area for several weeks will be helpful.
Prevention is better than cure. Practise good husbandry, prevent prolonged wetting by providing some shelter, examine regularly for parasites, and never expose a horse or groups of horses to confinement in small muddy paddocks without shelter.