Comparison of Sensitivities of Skin Prick and Intradermal Tests with Oral Rechallenge Test: A Prospective Interventional Hospital-Based Study

BACKGROUND: Identification of culprit drug causing adverse cutaneous drug reactions may not be possible clinically due to the intake of more than one drug. AIM: To compare the sensitivity of skin tests with gold standard oral rechallenge test to detect adverse cutaneous drug reactions. MATERIALS AND METHODS: This is a prospective interventional hospital-based study of patients with adverse cutaneous drug reactions attending the outpatient department of dermatology and venereology at a tertiary care center over a 12-month period. Skin prick tests, intradermal tests, and oral rechallenge tests were performed in these patients and their sensitivities were compared. The data of quantitative nature is presented in mean and standard deviation, and categorical variables are presented in number and percentage. The sensitivity of skin tests is compared with the gold standard oral rechallenge test. RESULTS: A total of 49 patients with adverse cutaneous drug reactions were evaluated. Clinical spectrum of adverse cutaneous drug reactions ranged from mild to severe, with fixed drug eruption being the commonest (55.1%) followed by maculopapular exanthem (32.7%). The highest incidence was with fluoroquinolones (43.8%) followed by nonsteroidal anti-inflammatory drugs. Fluoroquinolones were the major cause of fixed drug eruption followed by nonsteroidal anti-inflammatory drugs. The sensitivity of skin prick test and intradermal tests were 49% and 73%, respectively and the difference was highly significant (P < 0.001). The difference in sensitivity in skin prick test versus oral rechallenge test and intradermal test versus oral rechallenge test was also highly significant (P < 0.001). LIMITATIONS: Small sample size was a major limitation. Histopathological examinations and human leukocyte antigen associations could not be done. CONCLUSION: Predominant causative drugs were fluoroquinolones followed by nonsteroidal anti-inflammatory drugs. Sensitivities of skin prick test and intradermal test were quite good and these skin tests should be performed before oral rechallenge test in cases of adverse cutaneous drug reactions.