Eruptive Disseminated Porokeratosis (EDP) Following Interleukin-6 Inhibitor Biologic (Actrema®) and Corticosteroid Induced Immunosuppression

Introduction: Porokeratosis is a group of rare skin diseases that commonly present as brownish-red blanching papules with a well-defined, keratinized border. While most cases are idiopathic, porokeratosis lesions are believed to be formed from the expansion of abnormal epidermal keratinocytes activated by stressors such as infection, UV-irradiation, and immunosuppression. Most cases are asymptomatic, but Eruptive disseminated porokeratosis (EDP), an infrequent variant, can be pruritic and has a higher incidence of relapse. EDP can also associated with malignancies, serving as a diagnostic marker. Case Presentation: A 73-year-old white female with sudden onset of multiple non-tender and non-pruritic erythematous, blanchable, well-defined papules and plaques on her lower legs and forearms bilaterally. Two months prior, the patient was diagnosed with Giant Cell Arteritis (GCA) and started on 60mg prednisone. Three days before dermatologic presentation she was started on the Interleukin-6 inhibitor Tocilizumab (Actemra). Visual examination of the lesions with light and magnification was characteristic of porokeratosis. The patient was treated with topical twice-a-day EpiCeram and reports continuing improvement in her lesions after 3 months. Discussion: Acute, disseminated eruptions of porokeratosis are still not well understood and less than 4 cases related to biologics have been reported. Our case illustrates the obscurity of triggers for EDP and highlights the potential utility of EDP findings as a marker of paraneoplastic manifestation or other disease. The medical field needs to be aware of the multitude of triggers of EDP and its diagnostic implications such as underlying neoplasms and rapid disease progression for proper patient care.