ABSTRACT Nail toxicities are a frequent yet often underrecognized component of dermatologic adverse events in children receiving anticancer therapies. Both conventional cytotoxic chemotherapy and newer targeted agents can affect the nail matrix, nail bed and periungual tissues, producing a broad spectrum of clinical manifestations that range from asymptomatic pigmentary alterations to painful inflammatory conditions with functional impairment. Conventional chemotherapy most commonly induces manifestations such as melanonychia, leukonychia, Beau's lines, onychomadesis, onycholysis and nail fragility because of transient or sustained damage to rapidly proliferating nail matrix cells. These alterations typically involve multiple nails. Although generally self‐limited, their delayed onset and resolution, due to intrinsic nail growth kinetics, may complicate temporal correlation with drug exposure and may still affect patients' quality of life. In contrast, targeted therapies, particularly MEK inhibitors, are predominantly associated with inflammatory periungual toxicities such as chronic paronychia and periungual pyogenic granulomas, which may be painful, prone to bleeding, and functionally limiting the quality of life. Emerging agents, including BRAF inhibitors, multi‐tyrosine kinase inhibitors, mTOR inhibitors and ALK inhibitors, share partially overlapping nail toxicity profiles, though usually with lower frequency or severity compared with MEK inhibitors. Early recognition of characteristic nail patterns is essential to prevent unnecessary investigations, misdiagnosis, and avoidable interruption of oncologic therapy. Management is largely conservative and includes protective measures, topical therapies, systemic anti‐inflammatory agents when indicated, and procedural interventions for refractory periungual lesions. A multidisciplinary approach involving paediatric oncologists and dermatologists is crucial to optimize symptom control, maintain treatment adherence and preserve quality of life in paediatric patients.
Rapparini et al. (Sat,) studied this question.