1 - Serviço de Imunoalergologia, Centro Hospitalar Universitário de Lisboa Central
- Poster em congresso internacional: European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress 2023
Few cases of oat allergy have been described and its allergens haven’t been precisely identified. We report two cases of anaphylaxis due to oats ingestion.
Case 1 - 13-year-old boy with a history of atopic dermatitis and the use of emollients containing oat extract. He had an episode of generalized exanthema, dyspnea, dry cough, and labial angioedema, 20 minutes after the ingestion of a slice of cake made of oat flour. Three months later, he presented with a similar episode after eating a cereal bar containing oats. Skin prick tests (SPTs) and prick-by-prick were positive with oat flour extract and oats, respectively. Specific IgE levels were high for oats (68.10 KUA/L) and lower for other cereals such as barley, rye, wheat, and corn (1.23-4.87 KUA/L), which he was eating regularly. Allergen microarray immunoassay showed positive results for Ana o 2 (0,5 ISU-E) and Gly m 6 (0.6 ISU-E), but he tolerated cashew and soy.
Case 2 - 22-year-old man with a history of atopic dermatitis, allergic rhinitis, and nsLTP syndrome with non-anaphylactic reactions to peach and nuts. He presented with an episode of generalized exanthema, abdominal pain, wheezing, and diarrhea immediately after eating an apple crumble made of oats flour, which he had never tried before, and ripped apples, which he ate often. SPTs were positive for oat flour extract. Specific IgE levels were positive for oats (72.50 KIU/L) and lower for rice, barley, rye, and wheat (3.81-54.20 kIU/L), which he tolerated. An allergen microarray immunoassay showed positive results for several nsLTP (Ara h 9, Cor a 8, Jug r 3, Pru p 3, Art v 3, Ole e 7, Pla a 3), PR-10 proteins (Bet v 1, Aln g 1, Cor a 1.0401, Mal d 1, Pru p 1, Ara h 8, Act d 9); species-specific compounds from grass, weed and tree pollen, dust mites, and also species-specific food compounds - Ana o 3, Tri a 14 and Bos d lactoferrin.
These are two cases of anaphylaxis due to the ingestion of oats, with a demonstrated IgE-mediated hypersensitivity mechanism. In the first case, the chronic use of emollients with oats on damaged skin could have been the route of sensitization, as previously described. The second case happens in the context of multiple sensitizations, most of them with no clinical relevance. Immunoblotting could be important because no reports of oats allergy due to LTPs or PR-10 proteins were found. Both patients showed asymptomatic sensitization to other cereals and were advised to keep regular ingestion of all, except oats.
Palavras Chave: alergia alimentar, aveia, alergologia pediátrica, anafilaxia,