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Utility of patch testing for patients with drug eruption.
1Division of Dermatology, Showa University Fujigaoka Hospital, Kanagawa, Japan.
Clinical and Experimental Dermatology
|March 19, 2014
Summary
Patch testing is a safer alternative to oral provocation for identifying drug eruption causes. Positive results were most common with contrast media and antiepileptics, suggesting patch testing is useful for these specific drug classes.
Area of Science:
- Dermatology
- Clinical Immunology
- Pharmacology
Background:
- Drug eruptions are common adverse reactions to medications.
- Patch testing is a less dangerous alternative to oral provocation for identifying causative agents.
- The diagnostic utility of patch testing for drug eruptions remains debated.
Purpose of the Study:
- To determine the rates of positive patch test results in patients with drug eruptions.
- To analyze these rates based on the suspected causative drugs and clinical presentation.
- To assess the overall usefulness of patch testing in diagnosing drug-induced skin reactions.
Main Methods:
- Analysis of data from 444 patients tested for drug eruption between 1990 and 2010.
- Patch tests applied to the back under occlusion for 2 days.
- Results interpreted using the International Contact Dermatitis Research Group (ICDRG) scoring system.
Main Results:
- 100 out of 444 patients (22.4%) showed positive patch test reactions.
- Positive rates were 23.6% for maculopapular eruption and 20.0% for fixed drug eruption.
- Most positive reactions were to contrast media (41.1%) and central nervous system drugs (28.6%), particularly antiepileptics.
Conclusions:
- Positive patch test rates are influenced more by the specific causative drug than the clinical features of the eruption.
- Patch testing demonstrates utility when contrast media or antiepileptics are suspected.
- Further validation, standardization of materials and methods, and clear guidelines are necessary for optimal use of patch testing in drug eruptions.
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