Coexistent respiratory allergy and cystic fibrosis.

The prevalence of respiratory allergies and their effects on the course of 
cystic fibrosis (CF) were studied in 63 patients. Fifteen patients (24%) 
had respiratory allergies as defined by history, physical examination, positive allergy 
skin tests, nasal and peripheral eosinophilia, and reversible airway obstruction. Serum 
immunoglobulins on these 15 allergic CF and 22 nonallergic CF patients 
were elevated when compared with those in normal age-matched controls. The 
allergic CF patients had significantly higher IgE levels (mean 598 international 
units [IU] compared to 281 IU); IgG, IgM, and IgA levels 
were similar in the two CF groups. The clinical condition of 
the allergic CF patients, (Shwachman score) was better than the nonallergic, 
suggesting some modulating effect of respiratory allergy on the severity of 
the disease. 