In the Japanese Guidelines for Food Allergy (JGFA) 2021, the new chapter 12-9, 10, 11, 12 were added to cover allergies to crustaceans, mollusks, fish, fish roe, fruits, and vegetables. Crustacean, fish, fish roe, and fruit allergies are commonly encountered in clinical practice and can sometimes cause severe symptoms. In addition, because there is less data on their natural history than in the case of hen egg or milk allergy, and affected patients are often sensitized to a wide variety of foods due to the strong cross-reactivity of the major allergens, these patients tend to eliminate them more often than may be warranted.

Chapter 12 explained the age of onset, clinical type classification, prognosis, allergen components, diagnosis, and dietary treatment based on the latest data. We hope that this guideline will deepen the understanding of crustacean, mollusk, fish, fish roe, fruit, and vegetable allergens and will lead to more appropriate dietary treatment based on diagnosis.