464 NON-PARASITIC SKIN DISEASES 



in addition to the scrapings pluck a tuft of hair at the edge 

 of the diseased area and mount as above. Examine with 

 high power for the fungus along the hair near the roots. If 

 the scrapings are to be examined later, secure a larger 

 amount and put in a clean vial or ointment box. Smear 

 slides cannot be made with this very well after it has dried. 

 Usually it is best to boil it slightly in a 10 per cent, solution 

 of KOH. Centrifuge it and withdraw some material from 

 near the bottom with a pipette and mount with cover-glass. 



DANDRUFF. 



Definition. The presence of fine, grayish-white scales on 

 the skin or in the hair, which may affect the entire skin 

 surface or small circumscribed areas. 



Etiology. A mild superficial inflammation of the skin 

 resulting in excessive exfoliation of the epidermis. Dandruff 

 may be due to several causes, viz.: Bath soaps that are 

 too irritating or used too often; irritating medicinal prepa- 

 rations used on the skin, especially parasiticide preparations; 

 direct sunshine on short-haired animals, especially when 

 unaccustomed to it or those recently sheared. Parasites 

 are a frequent cause; a mild attack of the demodectic para- 

 sites will occasionally produce no other symptoms. Internal 

 disorders, especially digestive diseases favor the condition. 

 Very often no assignable cause can be discovered. 



Symptoms. The disease occurs chiefly on the upper 

 surface of the body, especially on the neck, under the collar 

 and along the back. The hair coat is dull and dry and the 

 skin is covered with small grayish-white scales or dust. 

 Itching is sometimes present. 



Diagnosis. The presence of the scales indicates the condi- 

 tion, and only the absence of parasites distinguishes it from 

 parasitic diseases. 



Prognosis. The disease runs a rather prolonged course 

 but continued treatment usually effects a cure. 



Treatment. Good nourishment is necessary if digestive 

 disturbances are suspected as the indirect cause. Internal 

 treatment with digestive tonics, especially preparations 



