[Diagnóstico de alergia inmediata para penicilina: estudio piloto].

Objectives: To confirm the presence of allergy to penicillin and amoxicillin by in vivo exposure tests in patients with a history of immediate reaction to these drugs. Methods: Observational, cross-sectional, descriptive and prolective study. Patients between 12 and 60 years old with a history of immediate reaction after administration of penicillin and/or amoxicillin were included. Skin prick and intradermal tests were performed with benzylpenicilloyl polylysine and penicillin G, as well as oral challenge with amoxicillin.

Results: Ten female and 3 male patients were included. The mean age was 39 years. In 84.6% of the cases the last adverse drug reaction occurred 10 years ago and in all cases it manifested with urticaria. Allergy to penicillin was corroborated in only 38.4% of cases. The most frequent adverse reaction after in vivo exposure tests was pruritus in 23%.

Conclusions: Patients with suspected penicillin allergy should be evaluated by in vivo exposure testing with major and minor determinants to corroborate or rule out allergic reactions and improve treatment conditions.