Up to 10% of the population claim to have a penicillin allergy. In fact, 85-90% of all patients with anamnestic penicillin allergy tolerate penicillins because they are not or no longer allergic.
Consequences of a supposed penicillin allergy are avoidance of beta-lactam antibiotics such as penicillins and cephalosporins. Alternative anti-infectives are often less effective, have more side effects, induce more resistance and cause higher costs.
Patients, who claim to have a penicillin allergy, are for example twice as likely to receive vancomycin and three times as likely to receive fluoroquinolones. They have 23% more C. difficile infections, 14% more methicillin-resistant staphylococcus aureus (MRSA) infections and 30% more evidence of vancomycin-resistant enterococci (AER).
Therefore, a suspected penicillin allergy should always be verified. In addition to in vitro tests, skin tests and oral provocation are available for testing.
A penicillin allergy does not has to last a lifetime: About 50% of patients with IgE-mediated penicillin allergy lose sensitivity 5 years after the last reaction (about 80% after 10 years!).
97-98% of patients with penicillin allergy confirmed by skin testing tolerate cephalosporins!
Patients, who urgently need to be treated with a beta-lactam antibiotic, a desensitization can be carried out at short notice.
Indication: patients with confirmed (positive skin test or in vitro test) or urgently suspected IgE-mediated immediate reaction to penicillin AND for whom there are no comparably effective alternatives.
Contraindication: Anamnesis of Stevens-Johnson syndrome, exfoliative dermatitis or erythroderma. A desensitization temporarily alters the immune response to the antibiotic in the sense of short-term tolerance, which enables a safe medication (if taken continuously!).
In a recent publication in BMJ 2018 there is a call for the deletion of incorrect information from patient files in order to keep optimal treatment options open for these patients. In addition, "patients with penicillin allergy" were found to have an almost 70% increased risk of new detection of MRSA (infection or colonization) and a 30% increased risk of detection of Clostridium difficile as a result of the alternatives (gyrase inhibitors, macrolides, clindamycin, etc.) used to avoid beta-lactam antibiotics.