Eosinophilic Cellulitis (Wells Syndrome): A Clinicopathologic Diagnosis in an Elderly Patient.

Eosinophilic cellulitis, also known as Wells syndrome, is a rare inflammatory dermatosis that may clinically mimic bacterial cellulitis and contribute to diagnostic delay. We report the case of a 72-year-old woman with a history of systemic lupus erythematosus and other autoimmune comorbidities who initially presented with bilateral lower extremity erythema and received antibiotic therapy for presumed cellulitis, with transient improvement. Three days after completing treatment, she developed recurrent pruritic erythematous plaques involving both upper and lower extremities, accompanied by edema and pain, without significant improvement following antihistamine therapy. Laboratory studies revealed peripheral eosinophilia (absolute eosinophil count 1.07 × 10³/µL) and elevated erythrocyte sedimentation rate. Punch biopsy showed eosinophil-rich interstitial and perivascular inflammatory infiltrates consistent with eosinophilic cellulitis, and the patient subsequently improved with systemic corticosteroid therapy. This case highlights the importance of considering Wells syndrome in patients with recurrent cellulitis-like eruptions, particularly when response to antibiotic therapy is incomplete or transient. Early biopsy and clinicopathologic correlation remain essential for accurate diagnosis and timely management.