Recent advances in the understanding of the penicillin urticarias.

The three major groups of immunoglobulins (gamma G, gamma A, and gamma M) associated with this disease are reviewed. The presence or absence of atopic disease may account for percentage variability of gamma A because reagins (skin-sensitizing antibodies) are found in this immunoglobulin. The gamma A is the antibody usually responsible for anaphylaxis, rather than the gamma G precipitins, so stressed in the past. All three immunoglobulins may be found in serum sickness, which could account for the complex nature of this type of penicillin urticaria. The merits of the immunological tests (penicilloyl-polylysine, benzyl penicillin, hemagglutination, basophil degranulation) for the detection of penicillin sensitivity are analyzed, particularly as each applies to the various types of penicillin urticaria (serum sickness, anaphylactic, dermographic, delayed dermographic, and simple chronic urticaria and the lupus diathesis). The penicilloyl-polylysine test is greatly overrated as a means of predicting possible anaphylaxis. The benzyl penicillin skin test properly performed is an excellent means of indicating this.