ABSTRACT
Case Report: With the growing trend of incorporating seeds in diet, hypersensitivity reactions have been progressively occurring but are rarely suspected. Linseed is a plant from the Linaceae family, and its seeds are increasingly used in bread. Despite being identified as an allergen capable of causing anaphylaxis, case reports are scarce. Female infant, 11 months old, with atopic dermatitis (AD), has been under cow's milk (CM) avoidance diet in the last 3 months due to CM allergy. At 10 months old, 15 minutes after ingesting a maze and sweet potato's bread, a perioral, axillar, and ear's pruriginous erythema developed, as well as nasal, palpebral, and malleolar angioedema. It was medicated with second-generation H1 antihistamine with symptom resolution after 6 hours. She avoided that bread and tolerated wheat bread. Prick to prick tests were positive for the suspected bread but negative for maze flour and raw and cooked sweet potato. After a detailed analysis of the bread's composition, linseed was identified, and prick to prick tests were positive with it. Due to COVID-19 restrictions, the patient has not yet performed oral challenge. A linseed allergy was the most likely diagnosis. Thus, we recommended avoiding this seed or any food that can contain it. Crossreactivity with other foods (wheat, peanut, rapeseed) and rape pollen is poorly understood, and its clinical relevance has not yet been determined. Hence, we did not perform any further investigation. This was a rare finding, and we did not find any report on infancy. This case should raise awareness for a growing trend of seed hypersensitivity. Therefore, this group of foods should be taken into account while we're investigating suspected allergic reactions to cereals and other grains.