Nonimmediate reactions
Of 377 patients evaluated for NIRs, diagnoses were confirmed in 43 (11.4%). Half (51%) were girls, and 39.5% atopic. The BLs involved were AX (72%), AX-CLAV (21%) and cephalosporins (7%).
Severe reactions were reported in three cases (one acute generalized exanthematous pustulosis, one exudative erythema multiforme, and one drug-induced hypersensitivity syndrome). Patients were diagnosed based on their clinical history; neither ST nor DPT were carried out because of the risks.
Except for the three patients with severe reactions, patch testing was carried out in all other children evaluated (n = 374). Two were positive to AX, one to PG, and one to cefotaxime.
A controlled DPT was performed in 370 children, yielding positive results in 36 cases (9.7%) (Table 2). Thirty cases were positive to AX, all with good tolerance to PV; two were positive to CLAV, with good tolerance to PV and AX; two were positive to PV; one to cefaclor, and one to cefixime. These latter two cases both showed good tolerance to PV and to AX.
Clinical entities induced by DPT included NIU in 21 (58.3%) cases (plus angioedema in 5), and MPE in 15 ( 41.6%)(See table 2). In all cases a full therapeutic dose was required to elicit a response. However, when we analyzed the interval from drug administration to reaction, there was a clear divergence: 30% of the positive cases presented a reaction within 24 h, while 52.7% responded only at day 6 or 7 (Figure 2). Less than 10% of positives started showing symptoms between days 2 and 5.
Is summary, of the total 11.4% positives cases within this group ST contributed to the diagnosis in the 1.1% and DPT in the 9.5%. Selective reactions were identified with AX (80%), PG (7.5%), cephalosporins (7.5%), and CLAV (5%). NIU and MPE were the most frequent entities.