*Review* **Eosinophilic Gastrointestinal Diseases in Inborn Errors of Immunity**

**Martina Votto 1,2,†, Matteo Naso 1,2,†, Ilaria Brambilla 2,\*, Silvia Caimmi 2, Maria De Filippo 1,2, Amelia Licari 1,2, Gian Luigi Marseglia 1,2 and Riccardo Castagnoli 1,2,\***


**Abstract:** Inborn errors of immunity (IEI) are disorders mostly caused by mutations in genes involved in host defense and immune regulation. Different degrees of gastrointestinal (GI) involvement have been described in IEI, and for some IEI the GI manifestations represent the main and characteristic clinical feature. IEI also carry an increased risk for atopic manifestations. Eosinophilic gastrointestinal diseases (EGIDs) are emerging disorders characterized by a chronic/remittent and prevalent eosinophilic inflammation affecting the GI tract from the esophagus to the anus in the absence of secondary causes of intestinal eosinophilia. Data from the U.S. Immunodeficiency Network (USID-NET) reported that EGIDs are more commonly found in patients with IEI. Considering this element, it is reasonable to highlight the importance of an accurate differential diagnosis in patients with IEI associated with mucosal eosinophilia to avoid potential misdiagnosis. For this reason, we provide a potential algorithm to suspect an EGID in patients with IEI or an IEI in individuals with a diagnosis of primary EGID. The early diagnosis and detection of suspicious symptoms of both conditions are fundamental to prevent clinically relevant complications.

**Keywords:** eosinophilic gastrointestinal disorders; eosinophilic esophagitis; inborn errors of immunity; immunodeficiency
