[Penicillin allergy]. / Penicillinallergi.

Patients are often labelled "allergic to penicillin" without adequate reason. Since penicillins are frequently the drugs of choice, this label should not be accepted lightly. The allergic reactions to penicillins are of immediate, accelerated, or delayed-type hypersensitivity. The most serious reactions are those of acute- and accelerated-type, which are both IgE mediated. Ideally, patients suspected of being allergic to penicillins should be tested in succession with RAST, skin testing, and per-oral provocation. Patients with serious infections and documented penicillin allergy should undergo desensitisation. Patients with penicillin allergy have a slightly increased risk of reactions to cephalosporins.