Eruptive Keratoacanthomas Arising Within Eosinophilic Annular Erythema

Eosinophilic annular erythema (EAE) is a rare skin disorder that presents abruptly with erythematous annular plaques. Typically, these plaques spread centrifugally with central clearing and recur in a relapsing-remitting pattern. Histologic findings consist of dermal perivascular to dense eosinophilic infiltrates, with preservation of the epidermis and subcutis. In this report, we describe a unique case in an 85-year-old woman characterized by a chronic course of EAE that was initially localized, along with the development of multiple keratoacanthomas (KAs) arising within the affected skin. The onset of EAE eruption followed biopsy and treatment of a basal cell carcinoma, potentially serving as a triggering event. Histologic analysis was consistent with EAE, characterized by dense eosinophilic infiltrates and lacking flame figures. Multiple KAs arose within these lesions. This case highlights a potential clinical association between EAE and KA development, in which the chronic inflammatory microenvironment from EAE increased the risk of KA development, given that persistent inflammation is a known contributor to tumorigenesis. Management included topical corticosteroids for symptomatic erythema and pain, alongside methotrexate therapy to promote KA regression. Further investigation is warranted to better characterize this relationship and its underlying mechanisms.