Acute Ecze^na in SoHpcds. Dorsal Aspect. 475 



that these factors will operate on a given susceptible subject 

 while on another thej- are without much effect. This suscepti- 

 bility is called a " dartrous diathesis" by the French writers, 

 while most English and American writers are willing rather to 

 find the hidden cause or causes in the disorder of internal organs 

 (digestive, hepatic, urinary, generative, haematic, trophic, infec- 

 tive, plethoric, atonic). 



ACUTE ECZEMA IN SOEIPEDS. DORSAL ASPECT. 



Head, neck, shoulder, back, under girths, breeching, crupper. Summer. 

 Mouhing. Heavy coat. Thin skin. Youth. Symptoms : erect hair, pa- 

 pular groups, hot, thick rigid skin, itching, abrasion, ulceration, encru.sting, 

 pustules, white spot and hair. Treatment: laxative, cooling diet, cleanli, 

 ness, pure air, shade, rest, alkalies, locally vaseline, astringents, dusting 

 powder, anodynes, tar water, creolin, etc. 



This shows itself especially on the head, the sides of the neck, 

 under the collar, or saddle, the circingle or crupper, the breech- 

 ing or general surface. In these cases the profuse secretion 

 of sweat, and the friction of the harness is a marked local factor 

 in its production. It often shows a preference for the summer 

 season, the period of shedding the coat, the heavy coated ani- 

 mal, the animal with white, tliin or delicate skin. Youth also 

 predisposes. 



Symptoms. There is usually erection or roughness of the 

 hair, and the formation at such points of minute papules like 

 .small peas collected in groups. The skin may feel hot, thick- 

 ened, lacking in pliancy, not to be pinched up in folds, the 

 panniculus is contracted and manipulation shows tenderne.ss. 

 Soon the papules flatten and desicate and more or less violent 

 itching sets in. The patient rubs or scratches himself, causing 

 deep red congestion of the surface or even abrasion, or ulcer- 

 ation. Apart from abrasion the .skin becomes covered with 

 crusts or even .scales which agglutinate tufts of hairs and dry 

 up and desquamate. 



In other cases the eruption advances from the condition of 

 papules to that of vesicles and even of pustules, though finally 

 drying up with the same pruritus as in the papular form. 



