[Clinical Approach to the Patient With Stevens-Johnson Syndrome And Toxic Epidermal Necrolysis. Part I: Epidemiology,...

Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe cutaneous manifestations of adverse drug reactions. This first review aims to provide an update on the epidemiological, pathophysiological, clinical manifestations, diagnostic, and prognostic aspects of these conditions.

To establish an updated clinical approach to SJS/TEN based on current evidence.

A search was conducted in indexed databases (PubMed, SciElo, LILACS), selecting 68 articles and 2 clinical guidelines from the Ministry of Health of Chile (MINSAL), from March to September 2024.

SJS/TEN affects genetically susceptible individuals with inappropriate immune responses triggered by drugs or non-pharmacological factors, leading to keratinocyte apoptosis and high mortality. Three hypotheses for T-cell activation are proposed: hapten/prohapten, p-i interaction, and altered peptide model. Key mediators include FasL, perforins, granzymes, and granulysin. Genetic factors, such as HLA alleles and CYP450 variants, influence susceptibility. Diagnosis relies on clinical and histopathological evaluation. Skin biopsy is crucial for confirmation, though treatment should not be delayed if there is a high suspicion. Tools such as causality algorithms and developing biomarcadores may aid in early identification of SJS/TEN, though further research is needed.

Diagnosing Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) is challenging due to their variable clinical presentations and similarities with differential diagnoses. Biopsy is essential, but histopathological findings do not always distinguish between forms of SJS and TEN. Causality assessment tools and advancements in biomarkers show potential, but further validation is needed. This initial review allows for understanding the rationale behind the recommendations outlined in the second part of the review.