Eosinophilic polymorphic and pruritic eruption associated with radiotherapy L59.9

Rueda et al. 1999

Eosinophilic, polymorphic, pruritic eruption syndrome is a rare "hypersensitive" skin reaction that occurs in connection with radiotherapy. The reaction was first mentioned by Rueda et al. in 1999. Since then, further cases have been published, mostly in female patients with cervical cancer, endometrial cancer, breast cancer and anaplastic large cell lymphoma (Barbu MA et al. 2023). The reaction can occur up to nine and a half months after radiotherapy.

Unexplained. Most cases described in the literature occurred in female patients treated with radiotherapy for cervical cancer, endometrial cancer or breast cancer. Barbu MA et al. (2023) describe two "atypical cases" of EPPER that occurred in men treated with EBRT plus hormone therapy. Since most cases involve tumors that are hormonally susceptible, it is possible that sex hormones play a role in the pathogenesis.

The syndrome typically occurs during radiotherapy or some time after completion of treatment. It is characterized by generalized erythematous, itchy flat papules or vesicles or blisters. The eruptions are not limited to the irradiated areas; the lower and upper extremities are also frequently affected.

The reaction is self-limiting. Under therapy with corticosteroids, antihistamines and UVB radiation, a resitutio ad integrum can occur within 14-21 days. In the meantime, further cases have been published, mostly in female patients with cervical cancer, endometrial cancer, breast cancer and anaplastic large cell lymphoma (Barbu MA et al. 2023).

Case description (Barbu MA et al. 2023): A 72-year-old man diagnosed with stage IIIA prostate cancer in January 2021 presented to our clinic for oncologic treatment. He had no comorbidities, was ECOG 0 . Due to his high-risk grouping, radiotherapy and androgen deprivation therapy (ADT) were started.

The total dose was 54 Gy in the target volume prostate, seminal vesicles and regional lymph nodes, followed by a boost to a total dose of 78 Gy in the target volume prostate and involved lymph nodes. 10 days before completion of radiation, the patient developed papular exanthema all over the body, especially on the legs. Under a 2-week course of corticosteroid therapy (decreasing prednisone dose with inhibitory proton pump protection), the skin lesions healed.

1. Abdelrahman W et al. (2018) Eosinophilic polymorphic and pruritic eruption associated with radiotherapy in a patient with primary nodal Merkel cell carcinoma. Int J Dermatol 57:864-866.
2. Barbu MA et al. (2023) Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy in two patients diagnosed with prostate cancer. Clin Case Rep 11:e7266.
3. Byrd JA et al. (2001) Eosinophilic dermatosis of myeloproliferative disease: characterization of a unique eruption in patients with hematologic disorders. Arch Dermatol 137:1378-1380.
4. Kim JS et al. (2015) Radiation-induced eosinophilic, polymorphic, and pruritic eruption in a pig skin model. Lab Anim Res 31: 204-208.
5. Löbelenz L et al. (2019) Eosinophilic polymorphic and pruritic eruption associated with radiotherapy: case report and overview of disease characteristics. Clin Exp Dermatol 44:567-569.
6. Rueda RA et al. (1999) Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy. Arch Dermatol 135: 804-810.