858 Eczema. 



it is usually unevenly thickened, forming thick and firm folds, 

 and between these, as also in other places, it secretes moisture ; 

 sometimes scales and scabs are also encountered. The disease 

 is accompanied from the commencement by intense itching, and 

 sometimes the eczema is obstinate and persistent. Eczema 

 occurring on the skin of the tip of the tail may lead to ulcer- 

 ation (tail ulcer) because the animal licks and gnaws the itching 

 place. 



Circuniscri])ed eczema arises rather frequently on the 

 bridge of the nose (E. nasi), on the cheeks (E. buccarum), on 

 the arch of the orbit (E. superciliorum), and on the neck (E. 

 nuchaO where its occurrence may be due to wearing a muzzle 

 or to the collar. In this form the lesion is generally moist and 

 scaly, although small vesicles may be seen around the diseased 

 parts, and on the neck, especially in fat animals, bleeding cracks 

 between the folds of the skin. At the elbow joint or hock a 

 chronic eczema may arise, which is evidently due to the irrita- 

 tion of lying or sitting on hard ground; it is characterized by 

 the formation of thick, horny scales, accompanied by slight 

 itching. In dogs the skin of the scrotum (E. scroti) or the pre- 

 puce, in bitches the lips of the vulva (E. vulva^) may be the only 

 localization of the disease, which is moist or vesicular on the 

 scrotum of the dog, and may lead to severe swelling of the loose 

 cellular subcutaneous tissue as a result of frequent rubbing of 

 the fine skin. In the neighborhood of the other natural open- 

 ings of the body the disease probably develops from the acrid 

 action of the excreta; so especially on the eyelids (E. palpe- 

 brarum) in consequence of inflammation of the conjunctiva and 

 of the lachrjTiial canal, on the lips, especially in the neighbor- 

 hood of the angles of the mouth (E. labiorum) also about the 

 anus and in the region of the perineum (E. ani). 



Of the circumscribed forms of eczema, the greatest impor- 

 tance attaches to eczema of the external ear and of the external 

 auditory meatus. This complaint is designated as inner ear- 

 worm or otitis externa, and has been studied especially by 

 Becker and Imhofer. Aside from the otitis externa, which de- 

 velops in distemper as a painless moist eczema and accompa- 

 lued by copious gray secretion (according to Lange in 50% of 

 distemper cases [see Vol. I]), eczema of the external ear de- 

 velops either at the same time with eczema of the other parts 

 of the skin, or mostly as an independent affection through the 

 influence of chemical irritants, although, at least in some of the 

 cases, microorganisms, especially pus cocci, may lie responsible. 

 According to Imhofer the infectious material penetrates from 

 the hair bulbs into the numerous glands of the auditory meatus 

 and starts an inflammatory process which finally produces a 

 connective tissue degeneration of the glands, in consequence 

 of which, this disease should be distinguished from eczematous 

 otitides and known as otitis externa genuina. Such a distinction 

 cannot, however, be made clinically. In consequence of the 



