Dictionary of Allergies .. Bird-Egg Syndrome

Allergy to egg is highly frequent in childhood. In general, children allergic to egg react principally to the ingestion of egg white. Egg yolk contains various proteins but the major allergens are contained in egg white. The principal allergens are ovalbumin, ovomucoid, ovotransferrin, and lysozyme. These proteins have been sequenced.In some cases, a relationship between type I hypersensitivity with respiratory symptoms due to bird antigens and allergy to egg yolk has been described. This association is known as bird-egg syndrome, which is caused by sensitization to chicken serum albumin (alpha -livetin) and is characterized by the development of respiratory and gastrointestinal symptoms after egg intake or after contact with bird antigens.

The initial symptoms are usually asthma with or without rhinoconjunctivitis due to contact with birds. Individuals first become sensitized to bird proteins (feathers, excrement, serum and meat) and subsequently develop egg allergy.Although bird-egg syndrome has been described principally in adults, especially in women, it can also affect children in whom the syndrome presents certain differentiating characteristics in relation to the more common sensitization to egg white. Gastrointestinal and respiratory symptoms are more common than cutaneous symptoms and sensitization to egg yolk is more frequent than that to egg white. In children with allergy to birds and egg, egg allergy is usually more persistent; tolerance is not always achieved and develops later. Sensitization to other aeroallergens is also greater in individuals with allergy to birds and egg.Sensitization to egg sometimes precedes respiratory sensitization to bird proteins, a process known as bird-egg syndrome [1].

Bird-egg syndrome is one example of the close connection of type I allergies involving inhalant and food allergens. The sensitization to airborn allergens was proved to preceed the allergy to ingestive allergens in several studies. Hypersensitivity reactions to bird (feathers, serum, droppings and meat) and egg yolk allergens are more frequently observed in bird fanciers (budgerigar, canary, parrot etc.). The pathomechanism of IgE-mediated bird-egg syndrome is different from pigeon fancier's lung (a form of extrinsic allergic alveolitis), which is not a subject of the present data collection.

There are some differences in prevalences and symptoms between bird-egg syndrome and food allergy to egg without sensitization to bird allergens. For example respiratory reactions are frequent in bird-egg syndrome, while they are rarely seen in patients with egg allergy only.. Molecular biological and allergenic properties of the major egg yolk allergens alpha-livetin (chicken serum albumin), apovitellenin I and VI have been presented.(Internet Symposium on Food Allergens 1(2):81-92 (1999) Up to now only little is known about the identity of feather allergens. Apart from bird allergens feather mites participate in the cross-sensitization to house dust mite. Chicken serum albumin (alpha-livetin) has been implicated as the causative allergen of the bird-egg syndrome. However, the clinical relevance of sensitization to this allergen has not been confirmed by specific challenge tests and environmental sampling. Chicken albumin (Gal d 5) is a partially heat-labile allergen that may cause both respiratory and food-allergy symptoms in patients with the bird-egg syndrome [2, 3].

In vitro, the suspected patients are investigated for budgerigar droppings (e77), budgerigar feathers (e78), budgerigar serum proteins (e79), canary bird feathers (e201), chicken feathers (e85), parrot feathers (e213), pigeon droppings (e7), turkey feathers (e89), finch feathers Re214,pigeon feathers (Re215).

References

1. Nevot Falcó S, Casas Ramisa R, Lleonart Bellfill R. Bird-egg syndrome in children. Allergol Immunopathol (Madr). 2003 May-Jun;31(3):161-5.

2. Quirce S, et al: Chicken serum albumin (Gal d 5) is a partially heat-labile inhalant and food allergen implicated in the bird-egg syndrome Allergy 2001 Aug;56(8):754-62

3. Wyss, M. et al:  "Bird-egg" und "egg-bird syndrome" (Bird-egg and egg-bird syndrome). Allergologie; 1991:14: 275-278.