Skin testing penicillin antigens

Does not identify those patients who react to a minor antigenic determinant (i.e., anaphylaxis) does not reliably predict the occurrence of late reactions patients with a negative skin test may still have allergic reactions to therapeutic penicillin... 

Mechanism It has been stated that in patients with penicillin-specific IgE antibodies who underwent successful penicillin desensitization, the data suggest that anti-specific, mast cell desensitization is responsible for the tolerant state and that mediator depletion plays no role (190). Additionally, the clinical observation that wheal-and-flare skin responses to penicillin often become negative with successful desensitization, while IgE responses to other antigens remain unchanged, also supports an involvement of an antigen-specific mechanism. Furthermore, both clinical reactivity and skin-test reactivity return within a few days, unless a tolerant state is maintained by continued drug administration. The author stressed that these findings show that the desensitized state depends on the... 

Benzylpenicilloic acid is the main hydrolysis product of benzylpenicillin and is able to elicit wheal and flare reactions when used in skin tests in some patients allergic to penicillins. It has therefore been considered as one of the minor antigenic determinants of penicillin allergy (Siegel and Levine 1964 Voss et al. 1966) although the precise chemical nature of the determinant(s) derived from penicilloic acid has not been elucidated. The proportion of patients responding in skin test to penicilloic acid varies between 21% and 55% (Table 1). 

There are, however, still a number of clinical arguments suggesting that patients who become sensitized to penicillins are sensitized by the penicillin molecules themselves as administered, and not by preformed impurities. If this were the case, it would be expected that sensitized patients would react not only to BPO antigens but also to the protein determinants present in high-molecular-weight residues of penicillin fermentation. Thorough experiments by Muller et al. (1970) have shown that patients sensitive to penicillin usually do not respond to such mold determinants in skin and serological tests. Furthermore, recent experiments by Neftel et al. (1982) have shown that the mode of administration of benzylpenicil-... 

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