Radiation-induced eosinophilic, polymorphic, and pruritic eruption in a pig skin model.

Eosinophilic, polymorphic and pruritic eruption associated with radiotherapy (EPPER) can occur in cancer patients after irradiation. In this study, we characterized the clinical and histopathological features of pig skin that developed widespread polymorphic and pruritic skin lesions following localized 50 Gy gamma-irradiation. The pigs developed pruritus 5-7 weeks after irradiation, and infiltration of the dermis by eosinophils was detected 4-7 weeks after irradiation. The irradiated animals also showed transiently increased numbers of peripheral eosinophils 5-7 weeks after treatment. Irradiation induced desquamation after 2-4 weeks, which and the desquamation gradually resolved after 7 weeks. These pathological changes correspond to those seen in irradiated human skin, indicating that this model could be useful for elucidating the pathogenesis of EPPER and for developing therapeutic and prophylactic methods.