AIM To evaluate the utility of patch test and cross-sensitivity patterns in patients with adverse cutaneous drug reactions(ACDR) from common anticonvulsants. METHODS Twenty-four(M:F = 13:11) patients aged 18-75 years with ACDR from anticonvulsants were patch tested 3-27 mo after complete recovery using carbamazepine, phenytoin, phenobarbitone, lamotrigine, and sodium valproate in 10%, 20% and 30% conc. in pet. after informed consent. Positive reactions persisting on D3 and D4 were considered significant. RESULTS Clinical patterns were exanthematous drug rash with or without systemic involvement(DRESS) in 18(75%), Stevens-Johnsons syndrome/toxic epidermal necrolysis(SJS/TEN) overlap and TEN in 2(8.3%) patients each, SJS and lichenoid drug eruption in 1(4.2%) patient each, respectively. The implicated drugs were phenytoin in 14(58.3%), carbamazepine in 9(37.5%), phenobarbitone in 2(8.3%), and lamotrigine in 1(4.7%) patients,respectively. Twelve(50%) patients elicited positive reactions to implicated drugs; carbamazepine in 6(50%), phenytoin alone in 4(33.3%), phenobarbitone alone in 1(8.3%), and both phenytoin and phenobarbitone in 1(8.33%) patients, respectively. Cross-reactions occurred in 11(92%) patients. Six patients with carbamazepine positive patch test reaction showed cross sensitivity with phenobarbitone, sodium valproate and/or lamotrigine. Three(75%) patients among positive phenytoin patch test reactions had cross reactions with phenobarbitone, lamotrigine, and/or valproate. CONCLUSION Carbamazepine remains the commonest anticonvulsant causing ACDRs and cross-reactions with other anticonvulsants are possible. Drug patch testing appears useful in DRESS for drug imputability and cross-reactions established clinically. METHODS Twenty-four (M: F = 13:11) patients aged 18-75 years with ACDR from anticonvulsants were patched 3-27 mo after complete recovery using carbamazepine, phenytoin, phenobarbitone, lamotrigine, and sodium valproate in 10%, 20% and 30% conc. in pet. after informed consent. . RESULTS Clinical patterns were exanthematous drug rash with or without systemic involvement (DRESS) in 18 (75%), Stevens-Johnsons syndrome / toxic epidermal necrolysis (SJS / TEN) overlap and TEN in 2 The implicated drugs were phenytoin in 14 (58.3%), carbamazepine in 9 (37.5%), phenobarbitone in 2 (8.3%), and lamotrigine in 1 patients, respectively. Twelve (50%) patients elicited positive reactions t Cross-reactions occurred in 6 (50%), phenytoin alone in 4 (33.3%), phenobarbitone alone in 1 (8.3%), and both phenytoin and phenobarbitone in 1 Three (75%) patients among positive phenytoin patch test reactions had cross reactions with phenobarbitone, lamotrigine, and / or lamotrigine or valproate. CONCLUSION Carbamazepine remains the commonest anticonvulsant causing ACDRs and cross-reactions with other anticonvulsants are possible. Drug patch testing appears useful in DRESS for drug imputability and cross-reactions established clinically.