Feasibility and Safety of Rapid Drug Desensitization for Chemotherapy-Induced Maculopapular Eruptions.

Background/Objectives: Chemotherapy drug (ChD)-induced maculopapular eruptions (MPEs) may interrupt optimal cancer treatment when no equally effective alternative therapy is available. Evidence supporting rapid drug desensitization (RDD) for delayed-type MPE remains scarce. We aimed to evaluate the feasibility and safety of RDD in patients with ChD-induced MPE. Methods: Adult patients with ChD-induced MPE who underwent RDD between January 2021 and January 2024 were evaluated. Delayed MPE recurrence was assessed until the subsequent chemotherapy cycle. Results: A total of 63 RDD procedures were performed in 10 patients with ChD-induced MPE, most commonly triggered by taxanes and platinum agents. The median onset of the index reaction was 60.0 h (24.0-336.0), and delayed intradermal tests were positive in 2 of 9 tested patients (22.2%). No delayed MPE recurrences were observed during the predefined follow-up period until the subsequent chemotherapy cycle. Immediate breakthrough reactions occurred in 3 of 10 patients (30.0%), corresponding to 17 of 63 RDD procedures (27.0%), and were limited to mild flushing and pruritus that resolved with antihistamines with or without low-dose corticosteroids. All RDD procedures were successfully completed without severe systemic reactions, and all patients were discharged on the same day. Conclusions: In carefully selected patients with delayed-type MPE, RDD appears to be a feasible and safe short-term strategy for enabling continuation of essential chemotherapy within the predefined observation period. As this pilot study includes a small and heterogeneous patient population with limited follow-up, the findings should be considered preliminary and hypothesis-generating and warrant confirmation in larger prospective studies with longer follow-up.