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Evaluation of adverse cutaneous reactions to aminopenicillins with emphasis on those manifested by maculopapular
1Instituto di Clinica Medica, Università Cattolica del S. Cuore, Rome, Italy.
Abstract:
We assessed 195 subjects with histories of adverse reactions to aminopenicillins, using 1) skin tests with penicilloyl polylysine (PPL), minor determinant mixture (MDM), benzylpenicillin (PG), amoxicillin, and ampicillin (read after 20 min and 48 h); 2) patch tests with PG, amoxicillin, and ampicillin; and 3) RAST for penicilloyls G and V. Oral challenges with ampicillin, amoxicillin, and penicillin V were administered to 34/60 patients reporting maculopapular reactions. Immediate hypersensitivity (IH), in most cases for both penicillin and aminopenicillins, was diagnosed (based on skin tests, RAST, or both) in 35 subjects who had suffered anaphylactic shock, or urticaria, angioedema, or both urticaria and angioedema. Thirty-three of the 60 subjects reporting maculopapular reactions presented delayed intradermal and patch-test positivity, indicating delayed hypersensitivity (DH), for ampicillin and amoxicillin, and three were also positive for PG. Diagnoses were confirmed with oral challenges in 18/33. The remaining 27/60 were negative in all allergologic tests, with oral-challenge confirmation in 16. Our findings highlight the importance of the amino group in DH to aminopenicillins. Moreover, the mean time interval between the last reaction and our tests was significantly (P < 0.01) longer in DH subjects (54.96 months) than in those with IH (18.62 months), suggesting that the time of testing is less important in cases of DH.
Insights
This study found that the amino group is crucial for delayed hypersensitivity reactions to aminopenicillins. Testing time is less critical for delayed hypersensitivity compared to immediate hypersensitivity.
Area of Science:
- Immunology
- Allergy and Clinical Immunology
- Pharmacology
Background:
- Aminopenicillins are common causes of allergic reactions.
- Distinguishing between immediate and delayed hypersensitivity is crucial for accurate diagnosis and management.
Purpose of the Study:
- To investigate the role of the amino group in delayed hypersensitivity to aminopenicillins.
- To differentiate between immediate and delayed hypersensitivity reactions to penicillin and aminopenicillins.
- To assess the utility of skin tests, RAST, and oral challenges in diagnosing these reactions.
Main Methods:
- 195 subjects with a history of adverse reactions to aminopenicillins were evaluated.
- Allergologic testing included skin tests (immediate and 48-hour readings), patch tests, and RAST (penicilloyls G and V).
- Oral challenges with ampicillin, amoxicillin, and penicillin V were performed in a subset of patients.
Main Results:
- Immediate hypersensitivity (IH) was diagnosed in 35 subjects with severe reactions (anaphylaxis, urticaria, angioedema).
- Delayed hypersensitivity (DH) was identified in 33 subjects reporting maculopapular reactions, with positivity for ampicillin and amoxicillin.
- The time interval between reaction and testing was significantly longer for DH (54.96 months) than for IH (18.62 months).
Conclusions:
- The amino group plays a significant role in delayed hypersensitivity to aminopenicillins.
- Testing time appears less critical for diagnosing delayed hypersensitivity compared to immediate hypersensitivity.
- Comprehensive allergologic evaluation is essential for accurate diagnosis of penicillin hypersensitivity.