Epidemiology of emergency room asthma in northern California: association with IgE antibody to ryegrass pollen.

To examine the relationship between allergy and acute attacks of asthma, we have examined adult patients with acute asthma presenting during a defined pollen season. Sera from 59 patients presenting with acute asthma to the David Grant Medical Center emergency room at Travis Air Force Base during the spring "epidemic" of asthma were assayed for IgE antibody (Ab) to five allergens (mite, cat, cockroach, ryegrass pollen, and ragweed) with RAST. Control sera were obtained from 34 patients without asthma and 25 employees. The results demonstrate that 92% of the patients with asthma had greater than 200 units of IgE Ab to ryegrass pollen (approximately 20 ng of IgE Ab per milliliter) compared to 14% of the control subjects (chi 2 = 69; p less than 0.0001; odds ratio = 69). Some of the grass pollen--allergic patients also had increased levels of IgE Ab to ragweed, but only 25% had greater than 200 units. In contrast, there was no significant difference between subjects with asthma and control subjects in the prevalence of IgE Ab to the three indoor allergens (mite, cockroach, and cat). Twelve percent of the patients with asthma compared to 5% of the control subjects had greater than 200 units of IgE Ab to one of these three (chi 2 = 0.98; p greater than 0.1; odds ratio = 2.5).(ABSTRACT TRUNCATED AT 250 WORDS)