620 ANAPHYLAXIS IN RELATION TO INFECTION AND IMMUNITY 



ANAPHYLACTIC OR ALLERGIC SKIN REACTIONS 



As was previously stated, if a protein, such as tubercle potein 

 (tuberculin), syphilis protein (luetin), glanders protein (mallein), etc., 

 is concentrated and applied to or injected into the skin or mucous mem- 

 brane in a local sera, and if the body-cells have been rendered anaphy- 

 lactic to this protein, a local reaction is produced characterized chiefly 

 by congestion and edema. This local reaction is regarded as analogous 

 to the urticarial or other eruptions accompanying general serum anaphy- 

 laxis (serum disease) and is regarded as an anaphylactic or allergic 

 reaction, although there are not sufficient data at hand to prove that the 

 mechanism of the local or skin reaction is identical with that of the 

 general and severe reaction which may follow an intravenous injection 

 of the protein. 



Etiology of Skin Reactions. Skin reactions are conducted by intra- 

 dermal injection; by application to an abrasion of the skin; by rubbing 

 into the intact skin or, as on mucous membranes, by mere contact, as 

 instillation into the conjunctival culdesac. In the first and second 

 methods trauma, due to the operation itself, is a factor in the production 

 of the resulting inflammation; likewise the intracutaneous injection of 

 practically any protein or non-protein substance will elicit a non-specific 

 inflammatory reaction providing the dose injected is large enough. I have 

 summarized the probable causes of various skin reactions as follows 1 : 



1. The true anaphylactic skin reaction, a specific process due to the 

 interaction of specific anaphylactic antibody and specific anaphylac- 

 togen, largely within or upon the cells and with the formation of a diffus- 

 ible irritant or the production of cellular shock, capable of producing 

 acute hyperemia, edema, and leukocytic infiltration of the skin. 



2. The traumatic and non-specific protein skin reactions which may 

 be caused (a) by trauma and the direct injection of an irritant used as a 

 preservative for the material, as phenol, or, to a preformed toxic and 

 irritant substance, as diphtheria toxin in the Schick test; (6) to the 

 production of a protein poison of irritant qualities by the action of 

 non-specific proteolytic ferments in the serum or derived from injured 

 cells, upon the protein of the patient's serum, devitalized cells, injected 

 protein, or all three. 



The intradermal test has proved the most delicate means of eliciting 

 a local anaphylactic response, but is also more likely to yield the non- 

 specific and traumatic reactions. Physicians conducting skin reactions 

 should carefully bear in mind the possibility of mistaking a pseudo- or 

 traumatic reaction for the true anaphylactic reaction, and also that 

 1 Bull Johns Hopkins Hosp., 1917, xxviii, 163. 



