Sarcoptic Mange
Sarcoptes scabiei var equi is rare in the USA but is the most severe type of mange in horses. The first sign is intense pruritus due to hypersensitivity to mite products. Early lesions appear on the head, neck, and shoulders. Regions protected by long hair and lower parts of the extremities are usually not involved. Lesions start as small papules and vesicles that later develop into crusts. Alopecia and crusting spread, and the skin becomes lichenified, forming folds. If untreated, lesions may extend over the whole body, leading to emaciation, general weakness, and anorexia. Negative skin scrapings do not rule out the disease; biopsy may establish a diagnosis. If suspected, sarcoptic mange must be treated. Organophosphate insecticides or lime-sulfur solution can be used by spraying, sponging, or dipping. Treatment should be repeated at 12- to 14-day intervals at least 3–4 times. Alternatively, the oral administration of ivermectin or moxidectin at 200 μg/kg can be attempted. Several treatments are required 2–3 wk apart. It is important to treat all contact animals.