Human herpesvirus 6 involvement in paediatric drug hypersensitivity syndrome

Background Human herpesvirus (HHV) 6 positivity in the context of drug hypersensitivity syndrome (DHS) may influence disease severity. Systemic corticosteroid treatment of those with DHS testing positive for HHV6 has been speculated to prolong the duration of disease. Objectives To evaluate whether paediatric HHV6-positive patients with DHS develop a more severe illness than those without presumed reactivation, and to evaluate the response to systemic corticosteroid treatment. Methods A retrospective case series of 29 paediatric inpatients treated for DHS and tested for HHV6 was undertaken. HHV6-positive and -negative patients were identified and stratified into groups treated or not treated with systemic corticosteroids to examine their disease severity on the basis of hospital length of stay (LOS), total number of febrile days (T-feb) and days until cessation of progression (CTP). Results Human herpesvirus6-positive patients had similar demographic characteristics to those of HHV6-negative patients, but had significantly longer hospital LOS (11.5 days vs. 5 days, P = 0.039), T-feb (12.5 days vs. 3 days, P = 0.032) and CTP (4 days vs. 2 days, P = 0.014). All HHV6-positive patients and most (80%) of the HHV6-negative patients received systemic corticosteroids. Among the HHV6-negative patients, those who received corticosteroids showed significantly shorter CTP than those who did not (3 days vs. 2 days, P = 0.043). Additionally, there was a trend towards shorter hospital LOS and Tfeb among HHV6-negative patients who received corticosteroids vs. those who did not, although these differences were not statistically significant. The most common inciting drugs included trimethoprim-sulfamethoxazole (34%), phenytoin (10%) and amoxicillin (10%). Conclusions Human herpesvirus6 positivity with DHS is associated with a more severe disease course. Treatment with systemic corticosteroids was associated with a trend towards reduced hospital LOS and Tfeb, and a significantly reduced number of days until cessation of progression.