Effect of Epinephrin Upon Skin Reactions to Pollen and to Histamine.

Abstract

Most “Allergists” assume that injection of epinephrin within an hour or two of the time of testing will cause false negative skin reactions. This drug is frequently given in an attempt to alleviate the symptoms of urticaria and to hasten the involution of the lesions. Skin sensitive patients were tested as before described to pollen or to histamine or to both, and non-sensitive individuals tested to the latter only. As a control the normal disappearance time of pollen or histamine wheals was determined. This factor was found to vary considerably from patient to patient but to be fairly consistent for the individual, and seemed unrelated to the test substance or type of skin. A series of intracutaneous injections was made, measurements were taken 15 minutes later and epinephrin solution (1-1,000), 0.3 cc. (M.V.) per 150 pounds of body weight was given subcutaneously. This amount is sufficient to give a definite systemic response in most patients within 10 to 15 minutes, and to alleviate the symptoms of asthma or hay fever. Fifteen minutes after the epinephrin injection a second set of welts was made parallel to and about 1 1/2 inches from the first set in the antecubital space and at the wrist. It was thus possible to observe the effect of this drug upon the involution of wheals already formed and the genesis of them when the test substance was injected 15 minutes after the epinephrin. The rate of involution of wheals of pollen or histamine was little influenced by epinephrine when compared with the control rate for that individual but itching was often much less after epinephrin. This drug in the above amount did not prevent the formation of definite positive skin reactions, in fact a few patients gave as large or larger reactions after epinephrin as before.