Noninfectious Signs that an Inborn Error of Immunity Might Be Lurking Beneath.

Inborn errors of immunity (IEI) are no longer defined solely by recurrent infection, and up to two-thirds of patients present with immune dysregulation affecting virtually all organs and systems. This article elucidates the cardinal noninfectious red flags of IEI, categorizing them by medical specialty to aid the generalist clinician. We highlight distinct phenotypes-from the atopy plus of STAT3 loss-of-function to the neurovascular strokes of deficiency of adenosine deaminase 2-that warrant immunologic investigation. Recognizing these patterns is imperative as early molecular diagnosis unlocks targeted, mechanism-based therapies, preventing irreversible organ damage and improving long-term survival.