4.52 DISEASES OF THE SKIN. 



fever. Sometimes, however, it occurs spontaneously, and without as- 

 signable cause, as is seen in the so-called " deadness " of the fingers 

 and toes. 



Hyperaemia and anaemia of the skin seldom require active treat- 

 ment. The application of cold is indicated in the former, and, in the 

 latter, warmth, combined with moisture, as well as the application of 

 cutaneous stimulants and stimulating friction, is the proper remedv. 



IV._ INFLAMMATION OF THE SKIN. 



UNDER this heading we treat of all the nutritive disturbances of 

 the skin in which an exudation is thrown out within its substance or 

 upon its free surface. However, it is questionable whether, strictly 

 speaking, all these forms of disease ought to be regarded as inflam- 

 matory, as, in my opinion, an interstitial exudation is neither a neces- 

 sary condition nor a sure criterion of inflammation. We shall not, 

 however, indulge in further discussion of the question, and, after the 

 example of Simon, in the following chapters, shall employ the term 

 dermatitis to signify a process attended by exudation. 



Infiltration of a somewhat extensive portion of skin results in the 

 so-called erythematous and erysipelatous inflammations. When the 

 infiltration is limited to small discrete spots of the capillary layer, -we 

 have the papular exanthemata. The variety of dermatitis, character- 

 ized by the formation of wheals or wales, proceeds from a more super- 

 ficial and extended infiltration. In the erysipelatous form of inflam- 

 mation, a simultaneous exudation upon the free surface of the cutis 

 often lifts the epidermis, forming vesicles and blebs of variable size. 

 An exudation upon the surface of the cutis, which elevates the epider- 

 mis into blisters, also occurs in other kinds of inflammation, both acute 

 and chronic, which are not attended by infiltration of the skin itself. 



The vesicular exanthemata consist in superficial inflammation 

 which, like catarrh, is characterized by exudation upon the free surface 

 of the skin, unaccompanied by serious organic lesion, while in the 

 pustular form the exudation contains an abundant admixture of young 

 cells. There are also forms of cutaneous inflammation where the dis- 

 ease of the cutis is accompanied by a morbidly profuse growth of epi- 

 dermis, the so-called psoriasis. Besides these varieties, which diffei 

 chiefly in the intensity of the inflammation and the seat of the exu- 

 dation, there are others distinguished by the peculiar character of the 

 course of the disease, and by the causes which produce it, and which 

 compel us to treat of them in separate chapters, in order to avoid the 

 classification under one head of dissimilar diseases. 



