Eosinophilic polymorphic and pruritic eruption during radiotherapy L58.9

Rueda et al. 1999

Eosinophilia, polymorphic and pruritic eruption during radiotherapy, in short also called EPPER, is a rare eosinophilic dermatitis of unclear genesis, which is observed in connection with radiotherapy of various malignancies (mainly patients with cervical and breast carcinoma, less frequently with other malignancies such as Merkel cell carcinoma).

The reaction is rare (only a few individual cases have been described so far). Epidemiological data are not available because of the rarity of the reaction

To what extent a local dose saturation (boost irradiation) of the tumor bed plays a role in triggering radiation-induced eosinophilic dermatitis is still unclear.

Especially women in advanced age who have been irradiated because of malignancies (cervical carcinoma, breast carcinoma, Merkel cell carcinoma). These reactions have not yet been observed in men or children.

Intensely itchy eosinophilic, erythematous, also papular and vesicular dermatitis, which can develop during the irradiation phase but weeks afterwards, inside and also outside the radiation field and persist for several weeks or months. Pustules or urticae and scratch-induced excoriations are observed less frequently (Löbelenz L et al. 2019). Remarkably, this peculiar dermatitic reaction can also be triggered at pig skin (Lee JE et al. 2007)

Perivasal stressed lymphocytic Infiltrate mixed with numerous eosinophilic granulocytes

The diagnosis is a diagnosis of exclusion. Based on the polymorphic clinical and unspezifischen histological picture it can only be made after exclusion of differential diagnoses and in knowledge of the radiotherapy.

Toxic radiation dermatitis: acute toxic dermatitis (limited to the radiation field).

Skabies: detection of scabies mites; duct structures

Bullous pemphigoid: exanthematic, vesicular clinical picture

Hypereosinophilia syndrome: Systemic eosinophilia (absent in eosinophilic, polymorphic and pruritic eruption).

Topical glucocorticoids, UVB irradiation (? - Garcia-Dondoso C et al. 2007)

The reaction is self-limiting.

The local side effects after radiotherapy are, depending on the dosage and the radiation site, mainly edema, sensory disturbances, pain, or movement restrictions and lymphedema.

Less understood are apparently immunologically triggered local and/or systemic reactions after radiotherapy such as:

• multiforme exanthema
• papular exanthema
• bullous pemphigoid
• as well as the eosinophilic, polymorphic and pruritic eruption described here.

Eosinophilic reactions of the lung(eosinophilic alveolitis) are known to occur after radiotherapy, even outside the actual radiation field (Hosono Y et al. 2018).

1. Garcia-Dondoso C et al (2007) Eosinophilic, polymorphic and pruritic eruption associated with radiotherapy (EPPER) in two patients with breast tumour. J Eur Acad Dermatol Venereol 8: 1102-1104
2. Hosono Y et al (2018) Radiation Pneumonitis with Eosinophilic Alveolitis in a Lung Cancer Patient. Internal Med 57:1281-1285.
3. Kim JS et al (2015) Radiation-induced eosinophilic, polymorphic, and pruritic eruption in a pig skin model. Lab Anim Res 31:204-208.
4. Lee JE et al (2007) Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy in a patient with breast cancer. J Am Acad Dermatol 56(2 Suppl):60-S61.
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.