45G DISEASES OF THE SKIN 



attack certain portions of the Iwdy more than others, particularly on the 

 skin of the snout between the stop to the nostril (Fig. 100), cheeks, 

 side of the skull, and between the toes; more rarely on the outside of 

 the legs, and in exceptionally rare instances it extends all over the body, 

 develops very slowly, beginning with redness and loss of the skin and 

 hair. It is indicated by a series of red spots which are painful, irregular, 

 swollen, and extend over the surface the size of a dollar to the palm of 

 the hand. These spots are caused by the formation of a large number 

 of pea-like nodules which are hard and firm. In some cases we find the 

 whole surface of the skin red, hard, and very painful to the touch. After 

 a short time the nodules become soft, discharge spontaneously a more 



Fig. 161. — Acne muzzle. 



or lesser amount of bloody pus, and contain in some cases cores of necrotic 

 tissue. 



Occasionally we see the coalescence of a number of these acne nodules, 

 so that the skin presents a bluish-red discoloration and becomes purulent 

 or sometimes necrosed, as if the skin was undermined by purulent 

 collections. This may appear all over the body. 



The "non-acarian" acne often presents symptoms similar to the 

 parasitic acne (dermodectic mange) and in every instance it is always 

 well to make a careful microscopical examination of some of the pus 

 sc^ueezed out of nodules to see if any of the acari are present. It has a 

 great tendency to extend in almost all directions, and the cicatrices 

 which appear after healing of the disease leave bare spots in different 

 parts of the body, pink in color, streaked with lines of black pigment 

 deposits. 



Therapeutic Treatment. — The treatment consists in the removal of 

 any known cause of the disorder — when the disease is located on the nose, 



