Eosinophilic Folliculitis Presenting as Persistent Pruritic Facial Papules: A Diagnostic Challenge

Eosinophilic folliculitis is a rare inflammatory dermatosis characterized by recurrent pruritic follicular papules or pustules with eosinophil-predominant inflammation. Although classically associated with immunosuppression, it demonstrates a broad clinical spectrum and may present diagnostic challenges. We report a 50-year-old woman with a several-year history of recurrent, severely pruritic facial papules initially attributed to chronic spontaneous urticaria, mastocytosis, or an atypical presentation of papulopustular rosacea. Histopathologic interpretation was initially reported as being consistent with an arthropod bite reaction. However, the failure to respond to all directed therapies prompted clinical suspicion of eosinophilic folliculitis. Targeted dermatopathologic re-review revealed a folliculocentric eosinophilic infiltrate diagnostic of eosinophilic folliculitis. The patient demonstrated a complete and reproducible response to oral indomethacin. Over longitudinal follow-up, she was subsequently diagnosed with systemic lupus erythematosus more than five years after the onset of the cutaneous symptoms. This case highlights the variable clinical and histopathologic presentation of eosinophilic folliculitis, the importance of clinicopathologic correlation in refractory facial eruptions, and the potential association with underlying immune dysregulation.