Cutaneous Adverse Events in Children Receiving Mitogen-Activated Protein Kinase Pathway Inhibitors.

BACKGROUND/OBJECTIVE: Mitogen-activated protein kinase pathway inhibitors (MAPKi) are increasingly used as targeted therapies for paediatric central nervous system tumours and other malignancies. Cutaneous toxicities, including xerosis, dermatitis, follicular-based infections, acne, and paronychia, are common and may result in significant morbidity and treatment interruption. METHOD: In this 18-month ambispective observational cohort study, 24 consecutive children receiving MAPKi at a tertiary paediatric centre were included. Patients were followed prospectively, with retrospective data collected for those already receiving therapy at study commencement. The incidence and spectrum of cutaneous adverse events (AE), predisposing factors and management strategies were documented. RESULTS: Overall, 21/24 (87.5%) patients developed at least one cutaneous AE, most commonly xerosis, dermatitis, hair changes, paronychia, and pustular skin infections. Most events were Common Terminology Criteria for Adverse Events (CTCAE) grade 1-2; however, a small number of patients required dose modification or temporary treatment interruption. CONCLUSION: These findings support early dermatologic assessment and proactive management of MAPKi-associated cutaneous toxicities. We propose practical caregiver-directed skin care recommendations to be introduced at treatment initiation to reduce morbidity and improve treatment tolerability.