742 LOC!AL CONGESTIVE AND INFLAMMATORY DISEASES. 



ceptible, gradually passing on to separation and desquamation 

 of the iijoper layers in a crnst-like manner ; there is, however, 

 no raw surface and no weeping. All through its course 

 the inflammatory action exhibits the true er}'tliematous t}'pe 

 as distinct from the phlegmonous, in which the subdermal 

 structures are often involved — seen in the so-called erythema 

 ohronicum exhibited in the persistently inflamed skin of the 

 heels of horses naturally possessed of much hair, but which 

 fashion has doomed to be removed. 



This acute exudative erythema seems in many, of its 

 features closely allied to the true catarrhal inflammation 

 eczema ; only in the latter the layers deeper than the rete, as 

 the papillary and true corium, are undoubtedly much involved, 

 which they are not here. 



Erythema Chronicuon. — This term has been applied to the 

 persistent erythematous condition of the skin of the heels — 

 commonly known as chapped heels, otherwise dermatitis ery- 

 thematosa — so frequently encountered during winter in horses, 

 the heels of which have been denuded of hair, and where there 

 has been much exposure to damp or cold draughts from cur- 

 rents of air while in the stable. 



Even the milder forms of this persistent erythematous in- 

 flammation are troublesome, much more so Avhen deeper-seated 

 tissues become invaded and impetigenous or ulcerative pro- 

 cesses supervene. 



Diagnosis. — Erythematous inflammation is individualized by 

 its situation in the superficial layers of the skin, by the non- 

 production of new material in the true dermis, and by the 

 absence of pus-formation. There may be exudation, even 

 extensive, and attended with scaling of the epidermis. It is 

 distinguished from its companion aft'ection, urticaria, by the 

 existence in the latter of evanescent soft swellings or patches ; 

 and from eczema by the presence in the latter of distinct 

 vesicles, which in rupturing form crusts on the surface of the 

 skin, and, when removed by itching, leave a weeping raw 

 surface. 



Treatment. — In the successful management of any cases of 

 idiopathic erythema local measures are of the first importance ; 

 attention must be given to the removal of all irritants, to 

 secure cleanliness and good sanitary conditions. 



