while damage to other nail unit anatomic areas can be wide-ranging.
Those are key findings from an evidence-based literature review published on July 21, 2021, in the Journal of the American Academy of Dermatology, as a letter to the editor. “Dermatologic toxicities are often the earliest-presenting and highest-incidence adverse events due to targeted anticancer therapies and immunotherapies,” corresponding author Anisha B. Patel, MD, of the department of dermatology at the University of Texas MD Anderson Cancer Center, Houston, and colleagues wrote. “Nail unit toxicities due to immunotherapy are caused by nonspecific immune activation. Targeted therapies, particularly mitogen-activated protein kinase pathway inhibitors, lead to epidermal thinning of the nail folds and periungual tissue, increasing susceptibility to trauma and penetration by nail plate fragments. Although cutaneous toxicities have been well described, further characterization of nail unit toxicities is needed.”
The researchers searched the PubMed database using the terms nail, nail toxicity, nail dystrophy, paronychia, onycholysis, pyogenic granuloma, onychopathy, targeted therapy, and immunotherapy, and reviewed relevant articles for clinical presentation, diagnosis, incidence, outcomes, and references. They also proposed treatment algorithms for this patient population based on the existing literature and the authors’ collective clinical experience.
Dr. Patel and colleagues found that paronychia and periungual pyogenic granulomas were the most common nail unit toxicities caused by targeted therapy. “Damage to other nail unit anatomic areas includes drug induced or exacerbated lichen planus and psoriasis as well as pigmentary and neoplastic changes,” they wrote. “Onycholysis, onychoschizia, paronychia, psoriasis, lichen planus, and dermatomyositis have been reported with immune checkpoint inhibitors,” with the time of onset during the first week of treatment to several months after treatment has started.
According to National Cancer Institute criteria, nail adverse events associated with medical treatment include nail changes, discoloration, ridging, paronychia, and infection. The severity of nail loss, paronychia, and infection can be graded up to 3 (defined as “severe or medically significant but not life threatening”), while the remainder of nail toxicities may be categorized only as grade 1 (defined as “mild,” with “intervention not indicated”). “High-grade toxicities have been reported, especially with pan-fibroblast growth factor receptor inhibitors,” the authors wrote, referring to a previous study.
The review includes treatment algorithms for paronychia, periungual pyogenic granuloma, nail lichen planus, and psoriasis. “Long-acting and nonselective immunosuppressants are reserved for dose-limiting toxicities, given their unknown effects on already-immunosuppressed patients with cancer and on cancer therapy,” the authors wrote. “A discussion with the oncology department is essential before starting an immunomodulator or immunosuppressant.”
To manage onycholysis, Dr. Patel and colleagues recommended trimming the onycholytic nail plate to its attachment point. “Partial avulsion is used to treat a refractory abscess or painful hemorrhage,” they wrote. “A Pseudomonas superinfection is treated twice daily with a topical antibiotic solution. Brittle nail syndrome is managed with emollients or the application of polyureaurethane, a 16% nail solution, or a hydrosoluble nail lacquer,” they wrote, adding that biotin supplementation is not recommended.
Jonathan Leventhal, MD, who was asked to comment on the study, said that nail toxicity from targeted cancer therapy is one of the most common reasons for consultation in his role as director of the Yale University oncodermatology program at Smilow Cancer Hospital, New Haven, Conn. “When severe, these reactions frequently impact patients’ quality of life,” he said.
“This study is helpful for all dermatologists caring for cancer patients,” with strengths that include “succinctly summarizing the most prevalent conditions and providing a clear and practical algorithm for approaching these nail toxicities,” he said. In addition to targeted agents and immunotherapy, “we commonly see nail toxicities from cytotoxic chemotherapy, which was not reviewed in this paper. Multidisciplinary evaluation and dermatologic involvement is certainly beneficial to make accurate diagnoses and promptly manage these conditions, helping patients stay on their oncologic therapies.”
The researchers reported no financial disclosures. Dr. Leventhal disclosed that he is a member of the advisory board for Regeneron, Sanofi, Bristol-Myers Squibb, and La Roche–Posay. He has also received research funding from Azitra and OnQuality.