<p>Background: Adults with food-protein-induced enterocolitis syndrome (FPIES) often develop severe abdominal symptoms after eating seafood. However, no investigation of a food elimination strategy for adult FPIES patients has been performed to date.</p><p>Methods: We conducted a retrospective cohort study of seafood-avoidant adults by telephone interview, based on the diagnostic criteria for adult FPIES reported by González et al. We compared the clinical profiles, abdominal symptoms, and causative seafoods between FPIES and immediate-type food allergy (IgE-mediated FA) patients. We also profiled the detailed intake-status of seafoods in adult FPIES patients.</p><p>Results: Twenty-two (18.8 %) of 117 adults with seafood-allergy were diagnosed with FPIES. Compared with the IgE-mediated FA patients, FPIES patients had an older age of onset, more pre-existing gastrointestinal and atopic diseases, more episodes, longer latency and duration of symptoms, more nausea, abdominal distention, and severe abdominal pain, and more frequent vomiting and diarrhea. In particular, abdominal distention—reflecting intestinal edema and luminal fluid retention—may be the most distinctive characteristic symptom in adult FPIES (p < 0.001). Bivalves, especially oysters, were the most common cause of FPIES. Strikingly, intake-status profiling revealed that many FPIES patients can safely ingest an average of 92.6 % of seafood species other than the causative species.</p><p>Conclusions: There are many differentiators between FPIES and IgE-mediated FA, which may reflect differences in the underlying immunological mechanisms. Although seafood FPIES is unlikely to induce tolerance, many patients can ingest a wide variety of seafood species after a long period from onset.</p>