DISEASES OF THE SKIN. 



INFLAMMATORY CONDITIONS OF THE CUTANEOUS 



MEMBRANE. 



Inflammatory symptoms of the skin vary according to their 

 intensity, character, or location. The slightest irritation may pro- 

 duce redness, either with or without s'<velling — this is defined as 

 erythematous inflammation; or we may have a formation of circum- 

 scribed, solid, firm protuberances, papillae, fistules, boils, or gran- 

 ulations. These are ascribed to exudations originating partially 

 in the papillary body, in the Malpighian membrane, and also in 

 the neighborhood of the follicles. 



The inflammatory exudation may become reabsorbed in certain 

 cases, so that after the acute period of the disease has passed the 

 epidermis, which has become loosened, is gradually desquamated in 

 the form of scabs or crusts. We also occasionally see a dark pig- 

 mentation after the disease has run its course. This originates 

 from the haemoglobin of the extravasated red blood-corpuscles. 

 If the inflammatory processes and exudations increase gradually 

 in the cutaneous tissue, we may observe two different results. 

 The inflamed location may become covered with a moist, liquid 

 exudation, or the horny layer of the epidermis is raised up by the- 

 fluid, and we may have vesicles which raise the granular layer of 

 the mucous strata, and also the deeper layer of the membrane 

 becomes destroyed in the affected region. In the first case it is 

 covered by the deep layers of the membrane; in the latter case 

 the upper surface of the corium is exposed, having lost its vesicu- 

 lar covering. 



The liquid which fills the small or large vesicles is deficient in 

 cells in the early stages of its formation, and the liquid is clear 

 or slightly yellow. Later it becomes turbid by the addition of 

 leucocytes, and a number of whitish-yellow cells fill the fluid. In 

 some cases it has this appearance from the very onset. "When the 

 liquid contained in the vesicle is yellow and filled \A'ith cells it is 

 called a pustule. Sooner or later the covering of the pustules 

 (384) 



