Histopathological analysis and clinical correlation of drug reaction with eosinophilia and systemic symptoms ( DRESS )

Summary Background Drug reaction with eosinophilia and systemic symptoms ( DRESS ) is a severe cutaneous adverse drug reaction. However, its histopathological features have not been well defined. Objectives To identify the clinicohistopathological findings of DRESS , and analyse the cutaneous histopathological changes observed in DRESS compared with those observed in maculopapular exanthema ( MPE ). Methods In a retrospective study, conducted at Chang Gung Memorial Hospital (Taiwan) between 2001 and 2011, we compared the clinicohistopathological features of 32 patients with probable/definite DRESS (defined by the Regi SCAR scoring system) with those of 17 patients with MPE . Results The major pathological changes observed in patients with DRESS included dyskeratosis (97%), epidermal spongiosis (78%), interface vacuolization (91%), perivascular lymphocytic infiltration (97%) and eosinophilic infiltration (72%). Many pathological features were common to both MPE and DRESS . However, severe dyskeratosis, epidermal spongiosis and severe interface vacuolization were significantly more prominent in cases of DRESS ( P  <   0·05). The presence of severe dyskeratosis was significantly associated with the clinical severity of renal impairment ( P  =   0·01). Conclusions The severe dyskeratosis detected in patients with DRESS may correlate with a greater extent of systemic involvement compared with that noted in MPE . However, the histopathological changes associated with DRESS are not entirely specific.