898 



Acanthosis Nigricans. Thickening of the Celhilai- Tissue. 



chiefly in .young animals from causes not exactly known. The places of predilection 

 of this skin affection are the axilla, the fohl of the stifle, the extensor side of the 

 toes, then the skin of the scrotum, the region around the anus, the under surface 

 of the tail, the lower belly, the under side of the neck, the region of the corners of 

 the mouth, the eyelids and the lips. On these places swelling of the skin and falling 

 out of the hair occurs, the skin being at first softer to the touch than usual, and, 

 in consequence of the more plainly prominent normal skin grooves, it appears like sha- 

 green or seal-skin leather (Fig. 129). With the simultaneous occurrence of a deep 



grayish blue to black-brown pigmenta- 

 tion isolated papillary or condyloma- 

 like elevations become plainly notice- 

 alile, parallel or crosswise ridges form 

 which se^jarate the furrows. In con- 

 sequence the skin becomes harder 

 and firmer or rough like a grater. 

 Slight exfoliation is noticed only ex- 

 ceptionally, but itching is generally 

 present. At times the process in- 

 volves the claws or the neighboring 

 mucous membranes, and in such 

 ca^e red, soft, not bleeding, granu- 

 lations are formed on the mucous 

 membrane. 



For the differential diagnosis 

 acariasis must particularly be con- 

 sidered, because in this disease the 

 deposit of pigment in the skin may 

 also occur, but it does not show a 

 symmetrical localization and the 

 abnormal pigment can be removed 

 together with the superficial layer of 

 the epidermis; moreover in acariasis, 

 mites are present in the skin. 



The treatment consists in the 

 emploAnnent of bran baths with sub- 

 sec(uent inunctions of fat, in the 

 internal use of arsenical preparations, 

 as well as in the employment of 

 salicylated alcohol (3%) or of ol. 

 Jecoris Aselli with 2-3% salicylic 

 acid. In the cases of the authors 

 10% naphthol ointment was used 

 with advantage, while Uebele 

 achieved success with 5% salicylic 

 ointment or with Esterdermasan, 

 provided any granulations that were 

 lasting cure is however not often ob- 

 Monh., 1909, XXI, 97 [Lit.].) 



Fig. 129. Acanthosis nigricans on the un- 

 der surface of the neck of a dog. 



present were removed with the scissors. A 

 tained, relapses being common. — (Habacher, 



Proscholdt found, on the inner surface of the ear of a horse, flat, warty, 

 generally unpigmented, more rarely pigmented papillary acanthomas, which arose 

 from a primary epithelial and secondary connective tissue proliferation. The 

 etiology is unknown. — (Proscholdt, Papillary Acanthoma, etc., Diss. Bern., 1908.) 



17. Thickening of Cellular Tissue. 



{Elephantiasis.) 



Pachydermia. 



On the posterior extremities of horses, very rarely on the head, 

 the skin, together with the subcutaneous connective tissue, may thicken 

 considerably as the result of long continued or frequently repeated in- 

 flammatory processes (eczema, erysipelatous inflammation, lymphan- 

 gitis, glanders), or from continuous venous stasis and edema. The affected 

 parts of the body become deformed and the legs resemble the thick 

 cylindrical limbs of an elephant, but if the head is affected it becomes 

 like that of a hippopotamus. On the feet the hypertrophy of the skin 

 and of the subcutaneous connective tissue commences at the coronet 



