Two cases of anaphylaxis by capelin with roe (Mallotus villosus)

Abstract

 Capelin (Mallotus villosus) is generally consumed as food in Japan. In Japan, people only eat female capelin with roe, not male capelin. Although capelin allergy is very rare, we have experienced two cases of anaphylaxis by female capelin with roe. The first case is a 6-year-old boy. He didn't have any history of food allergy. When he ate lunch that included capelin at school, he experienced anaphylaxis. Skin prick test (SPT) was positive for both roe and fish-body. Oral food challenge test (OFC) was positive for both roe and fish-body, which also caused anaphylaxis. Salmon roe and cod roe OFC were both negative. The second case is a 7-year-old boy. He did not have any history of food allergy. He developed eyelid edema after he ate capelin at home. SPT was weakly positive in roe and negative in fish-body. OFC was positive for roe, which also caused anaphylaxis. However, OFC was negative in fish-body. Cod roe OFC was negative. He could eat salmon roe without allergic symptoms at home. We assume that capelin roe has a specific allergen different from other types of fish roe.