Cutaneous Adverse Events Following Nemolizumab Administration: A Review

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by epidermal barrier dysfunction and immune dysregulation, with interleukin (IL)-4, IL-13, and IL-31 recognized as key mediators. Prurigo nodularis (PN) is another chronic inflammatory disorder driven by T helper type 2-mediated inflammation and neural dysregulation, leading to severe pruritus. Nemolizumab, a humanized monoclonal antibody targeting IL-31 receptor A, has been approved for use in the treatment of AD and PN. Clinical trials have demonstrated significant reductions in pruritus and cutaneous symptoms associated with its use. In clinical practice, acute eczema and edematous erythema frequently occur, occasionally necessitating the discontinuation of treatment. Despite these observations, no comprehensive review has examined nemolizumab-associated cutaneous adverse events. This review aimed to examine various cutaneous reactions associated with nemolizumab therapy, including psoriasiform eruptions, AD exacerbation, bullous pemphigoid, drug-induced eruptions, and fungal infections. Potential mechanisms underlying these reactions include T-cell activation due to drug sensitization, immune responses triggered by nemolizumab acting as a hapten, and a relative increase in IL-4 and IL-13 levels following IL-31 inhibition. However, the precise pathophysiological mechanism and risk factors remain unclear, and standardized clinical management guidelines are lacking. Further accumulation of clinical data and immunological research are essential for developing evidence-based strategies to manage these adverse events, ensuring treatment continuity and optimizing patient outcomes.