Diseases of the Skin 



1. Itching of the Skin. Pruritus Cutaneus. 



{J uchhranklieit .) 



An anomaly of function of otherwise apparently healthy 

 skin which manifests itself by continuous or temporary itching 

 of a more or less severe character is known as pruritus 

 cutaneus. 



This definition of itching does not apply to the cutaneous pruritus arising in 

 diseases of the skin connected with anatomical changes (eczema, nettle-rash, etc.), 

 or to the itching caused by animal or plant parasites. 



Neither does the name apply, strictly speaking, to the paresthesia similar to 

 itching which is seen now and again iu certain diseases of nerves, especially in 

 affections of the peripheral nerves. 



Etiology. General itching of the skin is ol)served at times 

 as a symptom accompanying chronic inflammation of the kid- 

 neys (Schindelka), chronic digestive ailments (Haubner, Schin- 

 delka) exceptionally also in jaundice, more frequently in dia- 

 betes melitus (Schindelka) as well as in shedding of the coat 

 (Haul)ner). In one horse it arose after an attack of influenza 

 (Pr. Mil. Vb.). Long continued feeding with maize and vetches 

 as well as the prolonged use of caffeine may cause a general 

 pruritus (Uebele). Further, according to Schindelka, it is not 

 rare in marasmic dogs. In cases noticed in dogs by Eberhardt 

 and by Frohner there was no primary disease. 



In opposition to the effect seen in human medicine, the prolonged use of arsenic 

 seems to produce hyperesthesia of the skin rather than pruritus if the employment 

 of the drug is interrupted periodically (Mayer). 



Certain organic diseases cause a local itching of the skin. 

 Thus pruritus ani is frequently due to the presence of intes- 

 tinal worms (tapeworms, oxjmriasis, gadfly larvae) in the rec- 

 tum of horses and dogs, while nasal itching results from pentas- 

 tomes and oestri. Finally Schindelka noticed pruritus of the 

 point of the tail in dogs without visible cause, while Frohner 

 saw obstinate itching on the left side of the lower jaw in a 

 horse. 



Pruritus localis appears also as a symptom in certain paresthesias such as 

 at the ])lace of the bite in hydrophobia, in acute infectious bulbar paralysis at the 



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