Abdominal allergic reaction syndrome: a tentative definition

Some patients with acute abdominal pain present with imaging findings suggestive of severe intestinal pathology, yet they remain hemodynamically stable and respond to corticosteroids rather than surgery. Recognizing this pattern early can prevent unnecessary laparotomy.

Three female patients (aged 91, 78, and 57 years) admitted to the emergency department presented with acute abdominal pain and diffuse bowel wall edema on a CT scan. Despite alarming imaging results, all three patients remained hemodynamically stable. The symptoms improved rapidly with intravenous methylprednisolone, and all patients were discharged without surgery.

We propose Abdominal Allergic Reaction Syndrome (AARS) as a preliminary recognition framework for this clinico-radiological pattern. AARS is not intended to replace specific diagnoses such as immunoglobulin A (IgA) vasculitis or lupus enteritis. Rather, it serves as an early identifier at a stage when the underlying etiology remains unclear. The core features (hemodynamic stability and clinico-radiological mismatch, supported by normal lactate levels) may help emergency physicians avoid unnecessary surgery while proceeding with the diagnostic workup. The term "allergic" is used here in its broader immunological sense (encompassing all type I-IV hypersensitivity reactions) and is not restricted to IgE-mediated reactions.