282 DISEASES OF THE SKIN 



Mange of the Horse. — ^Forms. — On the skin of the horse three 

 forms of mange mites appear. 



Sarcoptic Mange. — Definition. — This is the most important 

 form of mange in the horse because of its frequent occurrence 

 and the fact that it is more difhcult to cure than the other 

 forms. It attacks the skin of the body, neck and head and 

 tends to become general. 



Symptoms. — ^The skin lesions usually occur first about the 

 head, sides of the neck and shoulders and on the external sur- 

 face of the legs. If the case is neglected it can spread over 

 the whole body. The first symptpm is severe itching which 

 causes the animal to rub, bite and scratch itself especially 

 during warm nights. An examination of the affected parts 

 shows loss of hair, formation of papules, vesicles and crusts 

 under which the skin appears moist. The lesions tend to 

 increase peripherally, merging into larger, bald areas covered 

 with crusts, scabs or layers of desquamated epithelial cells. 

 In protracted cases the skin becomes thickened and ridged. 

 From the rubbing, biting and scratching secondary lesions 

 commonly occur. In about six weeks practically the whole 

 skin may become involved. Characteristic of mange is the 

 tendency to spread over the skin and the transmissibility to 

 other horses and even to man. 



Diagnosis. — The diagnosis depends upon the discovery of 

 the sarcoptic mange mite under the microscope. Otherwise 

 it is difficult to distinguish from the psoroptic or chorioptic 

 forms which in some cases may also involve the skin of the 

 entire body. As the mites are in tunnels under the epidermis 

 scrapings should be made deep enough to reach them and as 

 the number of mites found is generally limited several slides 

 should be examined before a negative opinion is given. 



Prognosis. — The prognosis is doubtful for unless circum- 

 scribed it may take several weeks of persistent treatment to 

 eradicate the mites and heal the skin lesions. 



Treatment. — Success in treating sarcoptic mange is largely 

 personal and lies not so much in the agent used as in the 

 thoroughness and the persistency of its application. The 

 following treatment is recommended: The affected animals 

 should be clipped and the manes roached. The removed 



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