Etiology. Symptoms. Treatment. 839 



of tlie coriiim and especially of the papillary bodies, but without 

 any iniportant change of the tissue structure (Erythema con- 

 gestivum) or at most with a slight serous infiltration of the skin 

 (E exudativum). The redness of the skin is thus, as a matter 

 of fact, the first stage of an inflammation of the skin. 



Etiolog-y. Primary erythema (E. idiopathicum) develops 

 under the influence of external irritants. The causes may be 

 trauma, for instance, pressure, friction, blow, bite, etc. (Ery- 

 thema traumaticum) ; thermic influences, such as scalding, burn- 

 ing, freezing, heat of the sun (E. caloricum and E. solare) ; al- 

 so chemical agents, namely, sharp, irritating substances like 

 vesicants (mustard, cantharides), volatile oils, mineral acids 

 and lyes in not too strong concentration, further the irritating 

 excretions of beetles and wasps (E. toxicum, s. E. venenis ab 

 acribus). In new-born dogs and cats, Schindelka has noticed 

 erythema lasting for several days (E. neonatorum). 



Secondary erythema (E. s^onptomaticum) is seen chiefly 

 ill the course of general infectious diseases, as in swine ery- 

 sipelas, swine plague and hog cholera, in distemper of the dog, 

 in smallpox, in foot-and-mouth disease. In those cases in which 

 erythema occurs after feeding on certain fodder, especially 

 clover, buckwheat, distillers' grains, lucerne, a pathogenic 

 effect on the cutaneous blood vessels is produced by a poison 

 absorbed from the digestive tract. 



Symptoms. Erythema is characterized by an increased 

 redness of the skin, and for this reason the disease is recog- 

 nized only in animals with unpigmented skin, namely, in sheep 

 and swine, and also on uncolored, white-spotted parts of the 

 skin of dark-haired or gray animals. The redness frequently is 

 seen only in spots as large or somewhat larger than a lentil (ma- 

 culae, roseolae) or in the form of larger congested spots which feel 

 hot and at the same time are pink; in both cases the redness dis- 

 appears under pressure from the finger but returns again soon. 

 If serous infiltration exists, the affected part of the skin appears 

 slightly swollen and eventually may show a yellowish color. In 

 many cases the development of erythema is accompanied by 

 itching, and then the affected parts of the skin are also slightly 

 painful. 



In most cases erythema lasts only a few hours or at most 

 a few days, and then disappears without leaving a trace. If 

 in exceptional cases it continues a longer time, the skin may 

 desquamate as it becomes paler. If, however, the erythema 

 occurs as the first symptom of an eruption or of a skin inflam- 

 mation, then the respective symptoms (nodules, vesicles, etc.) 

 usually develop as early as the second day. 



Treatment. Interference is necessary in erythema only 

 exceptionally, especially when it is accompanied l)y violent itch- 



