Type-I allergies in farming population

There is good evidence that type I sensitization occurs less frequently in farming people than in urban dwellers. The reasons for this are not clear. Adaptation or development of tolerance ("spontaneous hyposensitization") ma y play a role. In farmers, bronchial asthma and/or rhinopathy due to allerg y are mostly caused by mite allergens, especially by allergens from storage mites. Sensitizations to allergens from animal products is less frequent, very rare are sensitizations to swine and poultry. Allergies to pollen or m olds are also found in the general population, and it is sometimes difficul t to differentiate these from specific occupational causations in farming a ctivities. Consideration of biologic determinants (wind born) is helpful. H idden allergens are encountered in animal food, occasionally in fertilizer as well.