840 Nettlerash. 



ing and pain. In this case compresses of cold water, lead 

 lotion or Goulard's extract, or applications of alcohol seem 

 most suitable; neutral dusting powder or simple drjdng oint- 

 ments (lead or zinc oxide ointment) may also be employed. 



6. Nettlerash. Urticaria. 



{Quaddelausscldag, Nesselsuchf [German]; Echauhuulure 

 [French].) 



Nettlerash is characterized by roundish shallow elevations 

 on the skin which, in consequence of serous infiltration (of in- 

 flammatory origin) of the papillary bodies and of the Malpi- 

 ghian layer, develop very quickly and mostly disappear com- 

 pletely after a short time. 



Etiology. As a primary disease (Urticaria idiopathica) 

 nettlerash develops in a portion of the cases from the effects of 

 irritating chemical substances. Among these must be men- 

 tioned first of all the irritating juice of the stinging nettle (Urti- 

 caria urens and U. dioica) which may come in contact, especial- 

 ly with the bodies of horses and dogs while moving, rolling, or 

 lying on fields overgrown with stinging nettles (Eohr, Nicolas, 

 Brisavoine, Holterbach). A similar effect is produced by the 

 secretion of flies, ants, some caterpillars (processionary moth; 

 cnethocampa processionalis), the Kolumbcics fly, further by 

 drugs, such as oil of turpentine, carbolic acid, etc. In many 

 animals rubbing or scratching causes a similar eruption. Fi- 

 nally violent cold or cool wind exerting its effect on a heated or 

 sweating skin can cause urticaria, hence its frequent occurrence 

 in spring and autumn. 



Nettlerash is also due to certain chemical substances when 

 it follows the ingestion of food stuffs (Urticaria ex ingestis). 

 Thus one observes it in connection with feeding on green rye, 

 potato leaves, leguminosae, and in dogs at times after eating 

 chocolate or certain kitchen waste. A quick change of food can 

 also give rise to the trouble. Some individuals show a remark- 

 able hypersusceptibility (idiosyncrasy) in this respect, and as 

 a result they become ill regularly after partaking of certain 

 food stuffs, although these substances are harmless for most 

 animals. In all these cases the absorption of heterogenous 

 proteid substances appears to play the principal part, especially 

 if this material has caused an hypersusceptibility of the system 

 by its repeated absorption (see serum disease). 



Secondarily nettlerash develops rather frequently in con- 

 nection with acute gastro-intestinal catarrh and constipation 

 (Urticaria s^^nptomatica), especially in horses, more rarely in 

 dogs. Schindelka also saw nettlerash in one bitch at the time of 



