Bronchial hyperactivity, sputum analysis and skin prick test to inhalant allergens in patients with symptomatic food hypersensitivity.
BACKGROUND
Dyspnea may be a presenting symptom of type I food hypersensitivity; bronchial hyperactivity, without known asthma, can coexist in patients with food allergy.


OBJECTIVE
To evaluate airway involvement in young adult patients with food allergy and no asthma and compare the findings to those of patients with food allergy and asthma, with food allergy and allergic rhinitis, with asthma and no food allergy, and of apparently healthy controls.


METHODS
The evaluation involved prick skin test to food (65 allergens) and inhalants (24 allergens), spirometry, methacholine inhalation challenge, and induced sputum for cell analysis. The five groups consisted of 18 patients with food allergy alone, 11 with food allergy and asthma, 13 with food allergy and allergic rhinitis, 10 with asthma alone, and 10 controls.


RESULTS
Patients with food allergy alone were mainly (86%) skin sensitive to pollens. Those with either asthma or allergic rhinitis were mainly (95%) sensitive to mites. BHR was detected in 40% of the patients with food allergy alone, 55% of the patients with allergic rhinitis, and 100% of the patients with asthma. Cell counts in the sputum of patients with asthma and in those with food allergy and asthma showed higher eosinophil counts compared to those with food allergy and allergic rhinitis. Patients with food allergy and no asthma, regardless of BHR status, had mainly neutrophils in the sputum.


CONCLUSIONS
Patients with food allergy are highly likely to have concomitant asymptomatic BHR. Mite sensitivity in patients with food allergy predicts respiratory allergy (either asthma or allergic rhinitis). High eosinophil levels in the sputum of food allergy patients predict respiratory involvement.