Food Allergy - Classification

Classification

Food allergy is thought to develop more easily in patients with the atopic syndrome, a very common combination of diseases: allergic rhinitis and conjunctivitis, eczema and asthma. The syndrome has a strong inherited component; a family history of allergic diseases can be indicative of the atopic syndrome.

Conditions caused by food allergies are classified into 3 groups according to the mechanism of the allergic response:

1. IgE-mediated (classic):

• Type-I immediate hypersensitivity reaction (symptoms described above)
• Oral allergy syndrome

2. IgE and/or non-IgE-mediated:

• Allergic eosinophilic esophagitis
• Allergic eosinophilic gastritis
• Allergic eosinophilic gastroenteritis

3. Non-IgE mediated:

• Food protein-induced Enterocolitis syndrome (FPIES)
• Food protein proctocolitis/proctitis
• Food protein-induced enteropathy. An important example is Celiac disease, which is an adverse immune response to the protein gluten.
• Milk-soy protein intolerance (MSPI) is a non-IgE mediated allergic response to milk and/or soy protein during infancy and early childhood. Symptoms of MSPI are usually attributable to food protein proctocolitis or FPIES.
• Heiner syndrome — lung disease due to formation of milk protein/IgG antibody immune complexes (milk precipitins) in the blood stream after it is absorbed from the GI tract. The lung disease commonly causes bleeding into the lungs and results in pulmonary hemosiderosis.