Diagnosing nonimmediate reactions to penicillins by in vivo tests

Antonino Romano, Marinella Viola, Chiara Mondino, Rosa Pettinato, Marina Di Fonso, Giuseppe Papa, Alberto Venuti, Paolo Montuschi

Research output: Contribution to journalArticlepeer-review


Background: Maculopapular and urticarial rashes are nonimmediate manifestations common during penicillin treatment; the former often represent cell-mediated hypersensitivity. Our objectives were to assess the incidence of allergy in adults reporting nonimmediate manifestations during penicillin therapy and to evaluate the diagnostic potential of patch tests, delayed-reading skin tests and challenges in such cases. Methods: We used prick and intradermal tests as well as patch tests with penicillin determinants, ampicillin, amoxicillin and any other suspect penicillins. We also performed challenges with the suspect antibiotics. Results: Such antibiotics were aminopenicillins in 93.1% of 259 patients, most of whom had suffered from maculopapular rashes followed by piperacillin (4.2%). Three subjects displayed immediate skin test positivity. Ninety-four subjects showed patch test and delayed intradermal test positivity to the culprit penicillin (90 to aminopenicillins and 4 to piperacillin) and were considered as having had delayed hypersensitivity reactions. Five of the 8 subjects who displayed delayed intradermal test positivity and patch test negativity to the suspect penicillin underwent challenges, 2 reacted positively to the responsible aminopenicillin. Among the remaining 154 with negative results in allergologic tests, 125 agreed to undergo challenges; only 3 reacted. In all, 98 patients - 93 of whom had experienced maculopapular rashes - displayed delayed hypersensitivity (94 to aminopenicillins and 4 to piperacillin). Conclusions: Both patch and intradermal tests are useful in evaluating nonimmediate reactions to penicillins, particularly maculopapular rashes. Patch test and delayed intradermal positivity together indicate delayed hypersensitivity. Intradermal testing appears to be slightly more sensitive than patch testing.

Original languageEnglish
Pages (from-to)169-174
Number of pages6
JournalInternational Archives of Allergy and Immunology
Issue number2
Publication statusPublished - 2002


  • Challenges
  • Intradermal tests
  • Maculopapular rash
  • Patch tests
  • Penicillins

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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