Variability in the clinical pattern of cutaneous side-effects of drugs with systemic symptoms: does a DRESS syndrome really exist?

Conflicts of interest: none declared. Sir, In a recent study Peyrière et al.1 stated that the existence of a clinical entity, known under various names including HSS (anticonvulsant hypersensitivity syndrome), DRESS (drug reaction with eosinophilia and systemic symptoms), DIDMOHS (drug‐induced delayed multiorgan hypersensitivity syndrome) and DIHS (drug‐induced hypersensitivity syndrome) cannot be denied but that its definition, clinical and biological pattern, and limits must be more accurately reappraised. We can fully endorse that a gold standard is lacking, as is also repeatedly stated in the literature. Also the lack of consensus on nosology is obvious, but this is minor if there is agreement on what are the main characteristics of the ‘syndrome’. Although it is generally accepted that a syndrome by its nature comprises a variable combination of symptoms, the acronym DRESS is questioned as eosinophilia need not necessarily be present in this syndrome. The diversity of cutaneous adverse drug reactions is nearly infinite. It makes sense to isolate syndromes, rather than to consider the whole as a continuum, if it helps in finding original clinical patterns, courses, causes, mechanisms and treatment. From long discussions between experts from different countries in recent medical meetings on drug hypersensitivity it appears that whatever the denomination, HSS/DRESS is characterized by a variable combination of: (i) drug‐induced immunological background; (ii) later onset than other drug reactions; (iii) longer duration than common ‘drug rashes’; (iv) multiorgan involvement; (v) lymphocyte activation (node enlargement, lymphocytosis, atypical lymphocytes); (vi) eosinophilia; and (vii) frequent virus reactivation.