IgE-mediated reactions
Asthma, allergic rhinitis and allergic conjunctivitis may result following exposure to Chicken feathers, epithelial cells or droppings. The allergic manifestations may present as Bird Fancier´s Asthma and as Bird-Egg Syndrome, with symptoms such as rhinitis, urticaria and angioedema (2); and also as gastro-intestinal problems (3). Specific IgE has been found in patients exposed to Chicken feathers, and contact with Chicken has been reported as a common cause of occupational asthma and allergic rhinitis (8-11) (20).
Positive specific IgE tests with feather allergens have been reported in 20-60% of patients suspected to be allergic to feathers (12-14) . The clinical relevance of these results has not been fully established (20) .
Evidence of sensitisation to Chicken feathers is reported also in other studies. A Finnish study of 598 asthmatic children reported that 10% had specific IgE antibodies to Chicken feathers (7) .
Of 269 adult patients with suspected skin and respiratory allergies tested for feathers with skin-specific IgE tests, 9% of the whole group and 14% of those positive to inhalant allergens were positive to a feather allergen. Two reacted to Duck feathers, 12 to Goose and 15 to Chicken feathers. Symptoms were reported by 58% of feather skin-specific IgE-positive patients and by 55% of other skin-specific IgE-positive patients. Positive RAST-specific IgE test was surprisingly very low (20).
In a study of 507 asthmatic atopic children in the Chieti-Pescara area of Italy, specific IgE skin tests found that 5.9% were sensitised to feathers (15).
Chicken feathers are a significant cause of sensitisation in poultry workers. Asthma prevalence in farmers has been reported by means of a questionnaire survey to be higher for horse breeders/groomers, pig farmers, poultry farmers, and those working with oats. Up to 17.4% of poultry farmers reported symptoms of asthma (16). In an avian slaughterhouse, workers may be exposed to Chicken feathers, as well as to serum and droppings allergens (17). Sensitisation in these individuals may also occur to Chicken feed (18).
In a selected group of patients with known allergy to bird feathers, a high frequency (32%) of sensitisation to egg proteins, in particular egg yolk, suggests that in some patients feather sensitisation could trigger or somehow facilitate the later sensitisation to egg yolk proteins (Bird-Egg Syndrome) (19).
Clinical allergy to commercial feather products is less common than usually thought, as a result of the removal of dust, washing, and drying at 125 Celicus. The allergens derived from unrefined feathers include bird serum proteins, bird droppings, and feather mites.
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 Chickens (18) (21) or other birds such as Pigeons, Budgerigars, Parrots, Canaries, Parakeets, Cockatiels, Doves and Finches. Exposure results in the development of immunoglobulin antibodies including IgE (1), IgM (22), IgA and various IgG subclasses (23-25). The antibodies may be found in the sera and saliva of patients (26).
The allergenic proteins may be found in bird serum, droppings, and feathers. Contact may result from handling birds, cleaning their cages, or exposure to the organic dust drifting from where the birds reside.
Diagnosis is based on a characteristic clinical picture and a typical x-ray pattern, accompanied by the presence of specific IgG antibodies (27).
The measurement of specific IgG using IgG tracer technology has been shown to be a sensitive and specific assay for the routine diagnostic testing of extrinsic allergic alveolitis (28).
Other reactions
Farm workers handling animal feeds are exposed to a variety of chemicals, some of which may cause allergic contact dermatitis. A case of allergy to ethoxyquin (a preservative added to Chicken feed to inhibit vitamin degradation) in a Chicken farmer is reported (29).
Mites may also be a major allergen in poultry farmers. Northern Fowl Mite (Ornithonyssus sylviarum) residing in Chicken feathers may be the predominant allergen causing occupational allergy in poultry farmers (10) (30). The House Dust Mite, Dermatophagoides evansi, was documented in dust samples from poultry farms. Storage Mites and other predatory Mites were also found in these samples (31). Aleuroglyphus ovatus is a storage mite that has a worldwide distribution and has been found in stored bran, wheat, chicken meal, and dried fish products (32).
Polyester-filled pillows contain significantly more total weight of Der p 1 Mite allergen (Dermatophagoides Pteronyssinus) than feather-filled pillows (33).
