Pediatric emergency medicine trisk 1309 1309

DHR is a delayed-type hypersensitivity reaction that occurs to weeks, with an average of 22 days, after starting a medication Antiepileptics (carbamazepine, phenytoin, phenobarbital, lamotrigine) are the most common cause of DHR Other medications that commonly cause DHR are trimethoprimsulfamethoxazole, minocycline, dapsone, sulfasalazine, and abacavir There appears to be a genetic susceptibility for developing DHR to certain medications For example, HLA-A*31:01 is associated with an increased risk of DHR following exposure to carbamazepine in children Other associations with DHR include human herpesvirus-6 (HHV6), in which reactivation has been detected in cases of DHR Though the exact role of HHV6 in the pathogenesis of DHR is still unclear, some evidence suggests that HHV6 reactivation creates immune dysregulation that causes DHR, while others suggest that DHR-induced immune dysregulation allows for HHV6 reactivation The main differential diagnosis for DHR includes a cutaneous-limited morbilliform drug eruption, Kawasaki disease, and viral exanthem The presence of fever, facial edema, lymphadenopathy, and laboratory abnormalities distinguishes DHR from a cutaneous-limited morbilliform eruption The absence of conjunctivitis and mucous membrane involvement suggests DHR rather than Kawasaki disease The initiation of a potential high-risk medication weeks before rash onset increases the likelihood that an eruption is DHR rather than a viral exanthem