Allergic reactions to β-lactams – in vitro and in vivo diagnosis

Abstract

Rationale Since β-lactams allergy diagnosis is important to prevent allergic reactions we evaluated in vivo and in vitro methods contribution to β-lactams allergy diagnosis. Methods Sixty patients were evaluated having immediate allergy, after penicillin or β-lactams administration. All patients were evaluated with: 1-skin tests (PPL- benzylpeniciloyl-polylysine, MDM-minor determinants mixture, penicillin G, amoxicillin, ampicillin, cephalosporins); 2-Specific IgE (penicillin G, penicillin V, amoxicillin, ampicillin; 3-CAST (PPL, MDM, penicillin G, penicillin V, amoxicillin, ampicillin, cephalosporins). Sixteen patients have performed provocation tests to the relevant drug. Correlation analysis was performed using Spearman coefficient. Results Positive skin tests to at least one drug were identified in 25 patients, CAST revealed positive results to at least one drug in 26 patients, of which 16 have already had positive skin tests. All 4 patients with positive specific IgE had positive skin tests. Positive provocations were observed in only 4 patients, all having doubtful skin tests. The other 12 provocations were negative, all in patients with negative skin tests. As to skin tests, statistical analysis has revealed a good correlation between PPL and penicillin (rho=0,522 p<0,01), amoxicillin ( rho=0,403 p<0,01) and ampicillin ( rho=0,362 p<0,005). PPL test correlates very well with PPL CAST (rho=0,439 p<0,001). Conclusions Simultaneous evaluation of skin tests and CASTs, turned up to be useful to establish β-lactams allergy diagnosis, enabling to enhance diagnosis sensitivity. As negative skin tests were associated with negative provocations, it is suggested to use provocations tests only in patients with doubtful skin tests.