not developed symptoms of disease. The magnitude of this group within the population is of interest, however, because it reflects the proportion of the population at greatest risk of developing allergic disease. Additional exposure to the sensitizing allergen leads to the development of an allergic reaction (disease) that can be mild, moderate, or severe, depending on the amount of exposure.
The relationship between exposure, sensitization, and disease, and the potential for a threshold level of exposure below which the risk of sensitization is reduced, is of critical importance in the prevention and control of allergic disease. Epidemiological data would be useful in determining these relationships and in developing and evaluating public health and medical intervention strategies.
Research Agenda Item: Conduct appropriate epidemiological studies of exposure-response relationships of important defined indoor allergens that induce sensitization in humans. Such studies should include a focus on identifying threshold exposures.
Indoor allergens are associated with a wide variety of particles in a broad size range, only some of which are microscopically identifiable, culturable, or detectable with existing immunoassays. Evaluation of indoor allergens requires both air and source sampling, and several different analytical techniques (including microscopy, culture, and immunoassays) must be used to characterize even the well-known allergens. Because of the complexity of the assessment problem, indoor allergens, with a few exceptions, have not been identified and studied.
Research Agenda Item: Encourage and conduct additional research to identify and characterize indoor allergens. The new information should be used to advise patients about avoiding specific allergenic agents.
Although most studies investigate asthma (because it is common and can be measured objectively), sensitivity to indoor allergens is also very common among patients with other allergic conditions such as chronic rhinitis and atopic dermatitis. Because the important cause of inflammation that is common for all of these diseases is exposure to allergens, avoidance of the exposure should be the primary anti-inflammatory treatment. Developing realistic avoidance protocols for routine use is a challenge that must not take second place to pharmaceutical treatment.