Eosinophilic Annular Erythema: Clinicopathologic Analysis and Therapeutic Outcomes from a Multicenter Cohort

Introduction: Eosinophilic annular erythema (EAE) is a rare dermatosis characterized by persistent pruritic erythematous annular plaques with dermal eosinophilic infiltrates. It typically has a chronic, relapsing course with variable treatment responses and frequent refractory cases. Objectives: This retrospective multicenter study reports the clinical and histopathological features of EAE and the treatment outcomes in a case series of 10 patients. Methods: Ten patients with a confirmed clinical and histopathological diagnosis of EAE were referred to the Dermatology Departments of the University of Brescia and the University San Raffaele of Milan for evaluation and treatment. Results: The cohort included six females and four males, all Caucasian, with a median age of 56 years. Time from lesion onset to diagnosis ranged from two days to seven years. Patients exhibited annular, figurate, or polycyclic plaques with erythematous borders—dashed in 80% and centrally pigmented in 70% of cases. Intense itching was reported by 90%. Histopathology displayed dermal infiltrate primarily composed of lymphocytes with various numbers of eosinophils, ranging from scattered (10%) to abundant (40%) and numerous (50%). Treatment responses were variable, oral corticosteroids, either alone or in combination with hydroxychloroquine, being the most used therapies. However, flares frequently occurred following discontinuation of treatment. Dupilumab has shown promise in achieving long-term remission. Conclusion: Most patients exhibited pruritic lesions with dashed borders and central pigmentation, strongly suggesting a diagnosis of EAE. The positive response to dupilumab in refractory cases, along with long-term follow-up, reinforces the growing body of scientific evidence from case reports documented in the literature.