The importance of considering skin diseases from a temporal perspective: Special emphasis on the effects of corticosteroids and virally induced diseases

The efficacy and safety of medical therapies assessed on the basis of short‐term outcomes are often considered to inform the long‐term outcomes. Even in corticosteroid therapy, either systemic or topical, which is most frequently used as a first‐line therapy to control inflammation, few studies have reported the risk/benefit ratio for long‐term outcomes. Thus, a temporal perspective should be added to our conventional understanding of the effectiveness of medical therapies. In this review, we initially describe the importance of considering the efficacy of corticosteroid therapy based not only on short‐term outcomes, but also on long‐term outcomes of a certain type of severe drug eruption, drug‐induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DiHS/DRESS). Our view is exemplified by our recent analysis of previously reported cases of DiHS/DRESS, revealing that aggressive treatment such as pulsed corticosteroids and intravenous immunoglobulin, although beneficial in the short term, paradoxically has deleterious effects such as autoimmune sequelae in the long term. Thus, measuring the therapeutic efficacy from only a short‐term perspective is insufficient and follow‐up examination of these patients for at least three years is required even after complete resolution is observed. Various cutaneous diseases refractory to conventional therapies that occur after resolution of herpes zoster also require a temporal perspective to understand how cutaneous diseases develop at a certain site. We describe the clinical usefulness of considering the dual actions of corticosteroids, antiinflammatory, and immunostimulatory, depending on the situations in which they are used.