Acute Generalized Exanthematous Pustulosis Simulating Toxic Epidermal Necrolysis: Overlapping Processes

Pustulosis exantemática generalizada aguda simulando necrólisis epidérmica tóxica: forma combinadaTo the Editor:We read with interest the report by Horcajada-Reales et al. 1 of 2 cases with overlapping clinical characteristics involving acute generalized exanthematous pustulosis (AGEP) and toxic epidermal necrolysis (TEN).We would like to share a similar case we encountered in our practice.AGEP and TEN are well-established, distinct entities belonging to the group of severe cutaneous drug reactions.They both have characteristic clinical presentations and differ in pathogenesis, prognosis, and treatment.It is, however, sometimes hard to distinguish between the 2 conditions and this difficulty can lead to an erroneous clinical diagnosis.AGEP is a skin condition generally associated with a good prognosis.It typically presents as a rapidly evolving pustular eruption accompanied by fever and leukocytosis with neutrophilia.A skin biopsy reveals a subcorneal pustule.TEN, on the other hand, often affects the mucous membranes and is accompanied by fever and generalized discomfort, which precedes the appearance of eythematous-violaceous exanthema and epidermal detachment.Histological findings include epidermal necrosis and apoptotic keratinocytes.Our patient was an 82-year-old woman with no known allergies.She was admitted to hospital because of a 39 • C fever and a violaceous exanthema mainly affecting the trunk.The eruption was characterized by skin detachment in some areas and a positive Nikolski sign (Figs.1A and 1B).Laboratory testing revealed elevated transaminase levels: gamma glutamyl-transferase (GGT), 494 U/L; fatty acid (FA),