The diagnosis of DRESS syndrome often can be delayed, as children present acutely febrile and toxic appearing. Unlike many adverse drug reactions, DRESS syndrome does not show rapid resolution with withdrawal of the causative agent, further complicating the diagnosis. The typical onset of DRESS syndrome generally ranges from 2 to 6 weeks after the initiation of the offending drug; however, faster onset of symptoms, similar to our case, has been noted in antibiotic-triggered cases. In the prospective pediatric series by Sasidharanpillai et al,4 the average time to onset among 3 antibiotic-triggered DRESS cases was 5.8 days vs 23.9 days among the 4 cases of lamotrigine-associated DRESS syndrome.
Our patient demonstrated the classic features of DRESS syndrome, including fever, rash, lymphadenopathy, facial edema, peripheral eosinophilia, atypical lymphocytosis, and hepatitis. Based on the proposed RegiSCAR scoring system, our patient was classified as a “definite” case of DRESS syndrome.1,7 Other hematologic findings in DRESS syndrome may include thrombocytopenia and anemia. The liver is the most commonly affected internal organ in DRESS syndrome, with pneumonitis, carditis, and nephritis reported less frequently.1 The pattern of liver injury in our patient was mixed (hepatocellular and cholestatic), the second most common pattern in patients with DRESS syndrome (the cholestatic pattern is most common).8
The exanthem of DRESS syndrome can vary in morphology, with up to 7% of patients reported to have eczemalike lesions in the multinational prospective RegiSCAR study.1 Other entities in the differential diagnosis for our patient included Kawasaki disease, where conjunctivitis and strawberry tongue are classically present, as well as erythrodermic AD, where internal organ involvement is not common.2 Our patient’s exanthem initially was considered to be a flare of AD with superimposed bacterial infection and possible eczema herpeticum. Although bacterial cultures did grow Staphylococcus and Streptococcus, viral studies were all negative, and this alone would not have explained the facial edema, rapidly rising eosinophil count, and transaminitis. The dramatic drop in his eosinophil count and decrease in hepatic enzymes after 1 dose of intravenous methylprednisolone also supported the diagnosis of DRESS syndrome.
Treatment recommendations remain largely anecdotal. Early systemic steroids generally are accepted as the first line of therapy, with a slow taper. Although the average required duration of systemic steroids in 1 series of adults was reported at 50.1 days,9 the duration was shorter (21–35 days) in a series of pediatric patients.4 Our patient’s clinical symptoms and laboratory values normalized after completing a 1-month steroid taper. Other therapies have been tried for recalcitrant cases, including intravenous immunoglobulin, plasmapheresis, rituximab, and valganciclovir.2
Early clinical recognition of the signs and symptoms of DRESS syndrome in the setting of a new medication can decrease morbidity and mortality. Although DRESS syndrome in pediatric patients presents with many similar clinical features as in adults, it may be a greater diagnostic challenge. As in adult cases, timely administration of systemic corticosteroids and tapering based on clinical signs and symptoms can lead to resolution of the hypersensitivity syndrome.