Drug Induced Hypersensitivity Syndrome (DIHS) to carbamazepine, phenytoin, levetiracetam and quetiapine, a case of Multiple Drug Hypersensitivity (MDH) syndrome

Cross reactivity to structurally related aromatic anti-epileptic drugs is well known. These aromatic anti-epileptic drugs include phenytoin, phenobarbitone, carbamazepine and oxcarbazepine. Valproate, levetiracetam, clobazam and other anti-epileptics are preferred when there is history of hypersensitivity to aromatic anti-epileptic drugs as these drugs lack the aromatic structure which has been speculated to be involved in cross reactivity. Multiple Drug Hypersensitivity (MDH) syndrome is a distinct clinical entity wherein there is hypersensitivity to two or more structurallychemically and pharmacologically different drugs. This report describes an unusual case of drug induced hypersensitivity syndrome to phenytoin, carbamazepine, levetiracetam and quetiapine in a 26 year old G2P1L1 patient with seizure disorder. While phenytoin and carbamazepine have a common aromatic structure, levetiracetam and quetiapine have no structuralchemical similarity. This picture closely resembles that of MDH, management of which is challenging in a pregnant patient.