High-risk patients with a proven allergy to penicillin can safely receive cephalosporins, according to a letter published in the journal Allergy and Clinical Immunology.
The study included 50 patients (mean age 51 years; 78% women) with documented penicillin allergy who received 77 unique cephalosporins at the Yale-New Haven Hospital Health System between 2014 and 2022. Course or administration of the drug.
Among these patients, a history of atopy predominated: 38 (76%) met the labeling criteria for multiple drug allergy, and 19 (38%) index reactions had known reactions to aminopenicillins. Overall, 15 patients had a history of high-risk penicillin allergy and 35 patients had a history of low-risk penicillin allergy.
In addition, the investigators classified 35 (70%) reactions as low risk, including 28 cases of isolated rash, 4 cases of angioedema, and 6 cases of unknown reactions. There were also six cases of anaphylaxis, with four patients requiring adrenaline.
During skin testing, 19 patients (38%) were positive for ampicillin, 17 patients (34%) were positive for penicilloylpolysine, and 16 patients (37%) were positive for penicillin-G. In addition, 7 (14%) were selectively positive for ampicillin, and 14 (28%) were positive when challenged with the drug.
One patient responded to cephalosporins (2% of the entire cohort) and 1% of patients treated with cephalosporins. The patient’s medical history included asthma, chronic urticaria, and eight drug allergies.
The patient developed a pruritic, erythematous rash within one hour of taking the full dose during amoxicillin administration and responded to antihistamines and prednisolone. A month later, during administration of the drug cephalexin, the patient immediately developed urticaria, but this rash also improved with antihistamines.
The remaining 49 patients (98%) underwent 76 cephalosporin administrations, 52 of which used different side chains (68%) and 25 of which used similar side chains (32%).
Patients stratified into low- and high-risk groups received a significant proportion of cephalosporins with similar side chains, and no patients received cephalosporins with the same side chain, the researchers wrote. In addition, 21 of 22 patients (95.5%) receiving aminocephalosporins had no response.
Increasing the use of cephalosporins may reduce the higher risk of adverse outcomes experienced by patients with penicillin allergy, the researchers wrote, adding that based on these results, cephalosporins are often used even in patients with a proven penicillin allergy.
The researchers also call for future studies to evaluate whether these results apply to patients with a confirmed penicillin allergy who have recently experienced severe reactions.
However, the researchers note that these results will encourage further changes in cephalosporin prescribing patterns in accordance with recently updated drug allergy practice parameters.
Post time: Dec-05-2023