e78 Budgerigar feathers

IgE-mediated reactions

Asthma, allergic rhinitis and allergic conjunctivitis may result on exposure to Budgerigars (1, 2). The allergic manifestations may present as Bird Fancier´s Asthma and as the so-called Bird-Egg Syndrome, with symptoms such as rhinitis, urticaria and angioedema, and also as gastro-intestinal problems (3, 4).

In 212 sera from Budgerigar and Canary fanciers with symptoms of rhinitis and/or bronchial asthma, in 25 of 98 Canary feather-specific IgE antibody measurements, and in 28 of 154 Budgerigar feather-specific IgE antibody measurements, a significant level of specific IgE was found. In 3 sera, IgE antibodies against sera from both birds were present. IgE antibodies against Canary and/or Budgerigar feathers were present in about 20% of Canary and Budgerigar fanciers with symptoms of atopic disease. Canary and Budgerigar feathers contain IgE-binding antigens that are not present in the corresponding bird sera and droppings (2).

In a prospective study, 258 adults were investigated for sensitisation against bird antigens (Budgerigar, Canary, Pigeon) using an intracutaneous test. Eighteen of 78 Budgerigar keepers reacted against Budgerigar feathers. Thirty (38%) showed a positive skin reaction with at least 1 of the 3 extracts tested. In persons not exposed to birds, 18/96 (19%) were found to react to at least 1 of the 3 allergen extracts. Late reactions occurred in 5/70 (7%) Budgerigar keepers. The frequency of sensitisation against Budgerigar antigens increased to 48% of bird keepers (24/50) if the birds could fly around in their homes instead of being always caged (4/22, 18%). Three of the 78 Budgerigar keepers (4%) had a positive nasal provocation with feather extract, and they were skin-positive against all 3 bird antigens tested (3)

Extrinsic allergic alveolitis, also known as hypersensitivity pneumonitis, Bird Fancier’s Lung and Farmer’s Lung, is a disease of inflammation of the lung parenchyma in the terminal bronchioles and alveoli. Symptoms may start soon after exposure to bird allergens or after many years, and may include breathlessness, cough, occasional chills, and fever. Death may also result.

The disease occurs after exposure to organic dust, especially after close contact with Pigeons or other birds such as Budgerigars, Parrots, Canaries, Parakeets, Cockatiels, Doves or Finches. Exposure results in the development of immunoglobulins including IgE (1), IgM (8), IgA and various IgG subclasses (5, 6). The antibodies may be found in the sera and saliva of patients (7, 8) as well as in the sera of asymptomatic but exposed subjects (8)

The allergenic proteins may be found in bird serum, droppings, skin scales, feathers and, in the case of Pigeons, Pigeon bloom (a waxy fine dust which coats the feathers of Pigeons). Contact may result from handling birds, cleaning their lofts, or exposure to the organic dust drifting down from a ceiling or roof where birds nest.

Diagnosis is based on a characteristic clinical picture and a typical x-ray pattern, accompanied by the presence of specific IgG antibodies (9).

Other reactions

Feather Mites are a major source of soluble proteins derived from feathers, accounting for up to 10% of the total weight of the feather. RAST inhibition indicated feather Mites had species-specific epitopes as well as ones that cross-reacted with Dermatophagoides pteronyssinus (10).

The allergens have not been fully characterized yet.

Well-defined major allergenic bands with molecular mass of 20-30 kDa and 67 kDa have been detected and identified in IgE immunoblots with feather extracts as well as with serum proteins of Budgerigar, Parrot, Pigeon, Canary, and Hen. Inhalable feather dust was shown to contain several allergenic components which cross-react with serum allergens/antigens of the same as well as of other bird species (11).

Cross-reactivity

As noted above, inhalable feather dust contains several allergenic components which cross-react with serum allergens/antigens of the same as well as of other bird species (11).

Cross-reactivity between Chicken and other phylogenetically related bird species may be expected, and in Chicken-allergic patients significant IgE antibody titers to Parrot, Budgerigar, Chicken, Pigeon, Goose and Duck have been reported (4, 12), even in patients without known exposure(11).

Budgerigar and Hen feather and egg yolk alpha-livetin have been shown to have common epitopes, and the authors of the study suggest that alpha-livetin (Chicken serum albumin) leads to a cross-sensitisation and consequently to Bird-Egg Syndrome (13).

Last reviewed:April 2022