Abstract
Background/Objectives: Nemolizumab provides rapid and effective relief from pruritus in patients with atopic dermatitis. However, it is frequently associated with cutaneous adverse events, and reliable predictors of their severity have not yet been clearly identified. This study aimed to investigate the relationship between the severity of nemolizumab-associated cutaneous adverse events and patients' clinical background and to explore baseline factors that may be useful in predicting their severity. Methods: We retrospectively analyzed data from 40 patients with atopic dermatitis who received nemolizumab between May 2023 and March 2025. Clinical variables included demographics, prior therapies, phenotype, baseline Eczema Area and Severity Index subscores, serum biomarker levels, and treatment courses. The severity of cutaneous adverse events was classified as mild (<10% body surface area or limited to dryness/desquamation) or moderate-to-severe (≥10% body surface area). Results: Cutaneous adverse events occurred in 31 of 40 patients (78%); 13 were moderate-to-severe and 18 were mild. Most events appeared within 16 weeks of treatment initiation. Severity was associated with age, duration of disease, serum Thymus and Activation-Regulated Chemokine (TARC) level, and clinical phenotype. Patients with trunk-dominant phenotypes showed more severe cutaneous adverse events than patients with extremity-dominant or prurigo-type atopic dermatitis. Most cutaneous adverse events resolved within 12 weeks using topical therapy, without requiring treatment discontinuation. Conclusions: Baseline characteristics such as age, duration of disease, serum TARC levels, and severity of trunk lesions may be useful in predicting the risk of severe cutaneous adverse events, supporting their potential use in pre-treatment assessment and patient counseling.