850 Eczema. 



active animals (Cadeac), among which it may even occur as an 

 enzootic (Alix, AVoehrling), Accompanied l)y more or less se- 

 vere itching-, little papules and vesicles form, especially on the 

 orbital rims, on the neck, shoulders, thighs, at the root of the 

 tail and even over a large part of the trunk; these are only tem- 

 porary and are succeeded by fine scales and crusts which fall 

 off with the matted hair, and in this way small hairless patches 

 arise. By the occurrence of fresh eruptions this process is re- 

 peated in the surrounding skin, and larger, irregular, hairless 

 patches develop by coalescence of the small bald surfaces. 



As a result of long continued inflammation, the skin thick- 

 ens at these places, becomes rough, then dry, and scales continu- 

 ously (Eczema siccum) ; later on, however, it becomes moist and 

 covered with thick crusts under which a layer of purulent secre- 

 tion is often found, especially if the crusts are scratched off, 

 owing to severe itching. The trouble usually improves during 

 the winter but gets worse during the warm season, and can per- 

 sist on the same animal with such variations even for several 

 years, although occasionally it heals spontaneously. Darker 

 hairs often grow on the places that have previously been bald. 



The exact cause of the complaint is unknown. In some of 

 the cases on record the actual condition might have been scabies. 



In two eases mentioned liy Megnin, the affection occurred in strips which 

 crossed the long axis of the body vertically, like marks on a zebra, and these were 

 separated by healthy portions of skin. 



lodism of horses may sometimes make its appearance in the form of squamous 

 and crusty eczema, *and scales and scabs form on the si<les of the neck, shoulders, 

 head and hind limbs; the skin becomes thicker, especially over the posterior ex- 

 tremities; the affection has otherwise a great resemblance to bromine eruption 

 (Frohner). 



Eczema of the fold of the fetlock (socalled eczematous 

 greasy heal, Schrunden- or Schmutzmauke ; eaux aux jambes 

 aigues et chroniques) occurs in most cases on the thin skin at 

 the back of the fetlock, which is subjected to much external irri- 

 tation under the influence of dampness (dung, liquid manure, 

 watery feces) and of microorganisms. The direction of the hair 

 of the fetlock running parallel to the ground, the bend of the 

 fetlock and the regular folds in the skin predispose the part 

 to rhagadaB and eczematous disease. Frohner observed a case 

 of eczema affecting all four extremities in a horse after influen- 

 za, and presenting great similarity to malt and potato eczema. 

 Eczema of the fetlock usually commences as an acute disease 

 with the development of nodules and vesicles; later it_ usually 

 passes into a chronic form, leading to considerable thickening 

 and cracking of the skin, and to the formation of massive crusts. 

 The pain and tension of the diseased parts of the skin have a 

 prejudicial effect on the motions of the animal. 



Under the name of "Manle," various pathological processes are grouped to- 

 gether which differ both etiologically and in their course. Apart from eczema and 

 from the disease caused by the dermatophagus mite, one includes erythemas, ex- 



