DISEASES OF THE SKIN 



NETTLE-RASH— URTICARIA 



Urticaria is an acute skin disease in which the 

 cellular tissue becomes infiltrated with fluid from the 

 capillary blood-vessels, and flattened blotches or 

 swollen spots form on the skin. They are not lim- 

 ited to any particular region. This disease occurs 

 mostly in young pigs. 



Causes. — The most common causes of urticaria 

 are irritation to the skin by lice, dipping and sprink- 

 ling hogs with irritating solutions (kerosene emul- 

 sion), and filth. Well-fed young hogs seem to be 

 predisposed to this disease. Leguminous forage Crops 

 are said to cause it. It may accompany other dis- 

 eases, especially infectious diseases. 



Symptoms. — The blotches come on the skin very 

 suddenly, frequently during the night, and are most 

 numerous and noticeable on the ears, sides of the 

 neck, back of the arms, inside of the thighs, or 

 wherever the skin is thin. They appear as swollen 

 red spots that vary greatly in size. Several spots may 

 run together and form large blotches an inch across. 

 Because of the intense itching, the hog will scratch 

 and rub the inflamed skin, and the surface of the 

 blotches appears red and moist. 



While the irritation lasts the hog is very restless, 



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