Epidemiology of allergic diseases in children.

The one-year-prevalence rate of bronchial asthma in children varies from 1-3%, when investigated in general practice, to 5-7% in population studies. The prevalence rate is highest in young boys. Eighty percent of the asthmatic children are allergic, house-dust-mite allergy being the most common allergy. The one-year-prevalence rate of rhinitis is 5-10% in general practice, and 10-12% in population studies. Again, the prevalence rate is highest in young boys. About 90% of children with rhinitis symptoms are allergic, with pollen allergy as the most common allergy. Risk factors for developing allergic diseases are many. The predisposition is probably the most prevailing risk factor. Period of birth, sex, race, diet, the presence of other allergic diseases, tobacco smoking, pollution, and allergens in the environment, all these factors alone or in combination almost double the risk. There is no doubt that both asthma and hay-fever prevalences have steadily increased within the last 50 years. Also, admissions to hospitals for childhood asthma have continued to increase, while the mortality of asthma in children has not risen statistically. This increase is in contrast to the effective medication available for both asthma and allergic rhinitis, and to the number of preventive factors known to us today. The time has come to try to change it at all costs. The outcome of allergic rhinitis and asthma shows that only 10% are cured, 50% ameliorate, 30% remain unchanged, and 10% deteriorate. Factors determining the outcome are age, immunotherapy, sex, mother's age at childbirth, infections, other allergic diseases, and signs and symptoms of food allergy.(ABSTRACT TRUNCATED AT 250 WORDS)