Dermatophilus congolensis (Rain Rot) is a fungus. It occurs most frequently in domestic animals such as horses, goats, and sheep and has been found in wild and captive cervids such as deer, elk, and moose. It thrives in wet weather.
Clinical signs include raised, matted tufts of hair, scabs, and hair loss. Lesions initiated by biting flies (mechanical vectors) are found primarily on the back, whereas lesions induced by ticks are primarily on the head, ears, axillae, groin, and scrotum. People can get infected from contact. 

Diagnosis is done through laboratory testing which includes histopathology, cytology, culture of organism, and ELISA test.

There are different treatment methods. It is sensitive to a wide range of antimicrobials including erythromycin, spiramycin, penicillin G, chloramphenicol, streptomycin, amoxicillin, tetracyclines, and novobiocin.  Recovery is often within 2-3 weeks.