3. Results

109 patients with a discharge diagnosis of DRESS were re-validated. Of these, 3 were excluded, and there were 6 possible, 38 probable, and 62 definite cases of DRESS. Among the 100 cases of probable/definite DRESS, 93 cases had at least one viral marker studied and were analysed for this study (Supp Fig. 1).

3.1 Demographic and clinical characteristics

Of the 93 patients, 41 (44%) were men and 52 (56%) were women with an age range of 17 to 86 (mean (SD): 57 (17)) years (Table 1). The most common co-morbidities were hypertension (63%), hyperlipidemia(51%), and renal disease (32%). Associated systemic features include blood involvement (99%), hepatic involvement (72%), and renal involvement (44%)(Table 1). Slightly more than half of the cohort (54%) had 3 or more organs involved, and 37% of the cohort had 2 organ involvement.
3.2 Viral Reactivation
Thirty-nine (42%) patients were found to have viral reactivation of at least 1 of the human herpesvirus family (Table 2). Of these 39 patients, 12 (13%) patients had 2 viral reactivations and 3 (3%) patients were found to have all 3 viral reactivation on PCR assay testing. Specifically, HHV6 reactivation was the most common, occurring in 24/85 cases tested (28%). EBV reactivation occurred in 14/87 (16%) cases tested and CMV reactivation occurred in 19/89 (21%) cases tested. Twenty-two (24%) patients had more than 1 set of viral PCR tests carried out, and among them, 11 patients who initially tested negative, became positive on serial testing.