Mendelian randomization studies in atopic dermatitis: causal insights across omics layers

Atopic dermatitis (AD) is a chronic inflammatory skin disease, shaped by genetic, immune and environmental factors. Even though this complex interaction has been thoroughly studied, uncovering causal relationships between specific exposures and AD remains challenging. Mendelian randomization (MR) has emerged as a powerful tool for establishing causal inferences between exposures and outcomes, using genome-wide association data. MR studies have provided evidence for potential causal associations between AD and a broad spectrum of traits and comorbidities, including neuropsychiatric, cardiometabolic, oncologic, immune-mediated conditions, as well as ophthalmologic and infectious complications. Moreover, multi-omic MR approaches have enabled biomarker and therapeutic target discovery, highlighting opportunities for screening refinement, drug repurposing, and precision medicine. By integrating causal inference tools within multiple omics layers, MR is reshaping our understanding of AD, accelerating progress toward precision medicine in immune-mediated diseases.