Food additives and allergy.

There is ample evidence that food additives of several sorts may precipitate adverse reactions. Some of these have catastrophic potential such as sulfite sensitivity in asthmatic patients. Fortunately, asthmatic responses to a variety of additives are certainly not as prevalent as once feared, and are probably unusual. Restricted diets are of no general benefit in asthmatic patients. In contrast to asthma, urticarial or other cutaneous reactions to food additives are more common. A restricted diet for a few months' duration may be beneficial, although the mechanism through which this is achieved is unclear. Suspected food additive sensitivities are best documented by oral challenges, preferably in a double-blind manner. Challenges in asthmatic patients need to be done with patients continuing on their routine medications to avoid false positives. All care should be taken to titrate the doses and schedule the doses appropriately, since several of these agents could provoke large drops in pulmonary function. With urticarial patients, an adequate baseline of urticarial activity needs to be established before the challenges so that fluctuations in normal activity are not construed as a positive result. Despite a large number of studies evaluating the role of food additives in hyperkinesis, results are not uniform. Evidence does suggest that there is a small subset of primarily younger children in whom additives will impact on behavior. As with asthma and additives, the problem appears to be much smaller than originally postulated.