IgE-mediated hypersensitivity to cephalosporins: Cross-reactivity and tolerability of alternative cephalosporins

BACKGROUND: Studies regarding the cross-reactivity and tolerability of alternative cephalosporins in large samples of subjects with an IgE-mediated hypersensitivity to cephalosporins are lacking. OBJECTIVE: We sought to evaluate the possibility of using alternative cephalosporins in subjects with cephalosporin allergy who especially require them. METHODS: One hundred two subjects with immediate reactions to cephalosporins and positive skin test results to the responsible drugs underwent serum specific IgE assays with cefaclor and skin tests with different cephalosporins. Subjects were classified in 4 groups: group A, positive responses to 1 or more of ceftriaxone, cefuroxime, cefotaxime, cefepime, cefodizime, and ceftazidime; group B, positive responses to aminocephalosporins; group C, positive responses to cephalosporins other than those belonging to the aforementioned groups; and group D, positive responses to cephalosporins belonging to 2 different groups. Group A subjects underwent challenges with cefaclor, cefazolin, and ceftibuten; group B participants underwent challenges with cefuroxime axetil, ceftriaxone, cefazolin, and ceftibuten; and group C and D subjects underwent challenges with some of the aforementioned cephalosporins selected on the basis of their patterns of positivity. RESULTS: There were 73 subjects in group A, 13 in group B, 7 in group C, and 9 in group D. Challenges with alternative cephalosporins (ceftibuten in 101, cefazolin in 96, cefaclor in 82, and cefuroxime axetil and ceftriaxone in 22 subjects) were well tolerated. CONCLUSIONS: Cephalosporin hypersensitivity does not seem to be a class hypersensitivity. Subjects with cephalosporin allergy who especially require alternative cephalosporins might be treated with compounds that have side-chain determinants different from those of the responsible cephalosporins and have negative pretreatment skin test responses

Tolerability of aztreonam and carbapenems in patients with IgE-mediated hypersensitivity to penicillins

BACKGROUND: Studies performed on samples larger than 100 subjects with a documented IgE-mediated hypersensitivity to penicillins have demonstrated a cross-reactivity rate of approximately 1% between penicillins and both imipenem and meropenem, whereas a single study found a cross-reactivity rate of 6.2% with aztreonam in 16 such subjects. OBJECTIVE: To assess the cross-reactivity and tolerability of aztreonam and 3 carbapenems (imipenem-cilastatin, meropenem, and ertapenem) in patients with documented IgE-mediated hypersensitivity to penicillins. METHODS: A total of 212 consecutive subjects with immediate reactions to penicillins and positive results on skin tests to at least 1 penicillin reagent underwent skin tests with aztreonam and carbapenems; subjects with negative results were challenged with escalating doses of aztreonam and carbapenems. RESULTS: All subjects displayed negative skin test results to both aztreonam and carbapenems; 211 accepted challenges and tolerated them. Challenges were not followed by full therapeutic courses. CONCLUSIONS: These data indicate the tolerability of both aztreonam and carbapenems in penicillin-allergic subjects. In those who especially require these alternative β-lactams, however, we recommend pretreatment skin tests, both because rare cases of cross-reactivity have been reported and because negative results indicate tolerability

Reply

To the Editor: We read with great interest Drs. Baldo and Pham’s observations1 concerning our article2 and specifically their final claim that in selecting alternative cephalosporins in cephalosporin allergic subjects, “similarities and differences between R1 groups need to be noted but failure to do likewise for the R2 groups may lead to serious consequences for the occasional patient”

Guidelines for the use and interpretation of diagnostic methods in adult food allergy

Food allergy has an increasing prevalence in the general population and in Italy concerns 8 % of people with allergies. The spectrum of its clinical manifestations ranges from mild symptoms up to potentially fatal anaphylactic shock. A number of patients can be diagnosed easily by the use of first- and second-level procedures (history, skin tests and allergen specific IgE). Patients with complex presentation, such as multiple sensitizations and pollen-food syndromes, frequently require a third-level approach including molecular diagnostics, which enables the design of a component-resolved sensitization profile for each patient. The use of such techniques involves specialists' and experts' skills on the issue to appropriately meet the diagnostic and therapeutic needs of patients. Particularly, educational programs for allergists on the use and interpretation of molecular diagnostics are needed