Subjects in this group, when carefully questioned, recalled previous episodes of asthma, often occurring during childhood or they recalled having been diagnosed as asthmatic by a physician. In other subjects in this group, a strong suspicion of a past asthmatic condition was recognized during the USF examination. Usually, these subjects described an asthmalike process during childhood or early adulthood (frequent wheezing with infections, wheezing with pet animal exposures, “repeated bouts of bronchitis,” “allergies with wheezing,” etc) but no actual asthma diagnosis was confirmed by a physician. These latter cases were considered to represent preexisting asthma. In order for subjects with preexisting asthma to qualify for the study, there must have transpired a remission of asthma lasting for at least 1 year (and usually for many years); during this time, the patient experienced no asthma manifestations. In these patients, the available medical records documented that no asthma medications were taken and no physicians were consulted during the remission period.
The allergy/atopy status was documented for the 86 subjects as follows: 46 (53%) persons were decided by either allergen skin testing or RAST; for 12 (14%) individuals, a personal history of an allergic disease was noted; in one (1%) subject, there was an elevated total IgE level. Finally, there were 27 (31%) persons in whom atopy/allergy status was based solely on a family history of allergy.
For the 86 subjects in the study population, allergy/atopy occurred in 46 persons. Of these 46 allergic/atopic individuals, 37 (80%) subjects suffered irritant-induced asthma (p<0.01); one (2%) individual had allergic occupational asthma; and eight (17%) subjects were considered to have asthma that was not of occupational/environmental origin.
For the 37 subjects with irritant-induced asthma who were considered to be allergic/atopic persons, the allergy/atopy status was established by the following: allergic skin testing/RAST battery in 27 (73%); personal history of a known allergic disorder in three (8%); elevated total IgE in one (3%); and family history in six (16%).