A 3-year-old boy was examined for a three-month history of coughing and wheezing. There was no associated fever, weight loss, or night sweats, and no family illness. Moreover, there was no history of foreign-body aspiration, of travel to endemic disease areas, or of exposure to pets and birds. Treatment with theophylline and erythromycin for presumed asthma and bronchitis had not resulted in significant improvement.
On physical examination he had bilateral inspiratory and expiratory wheezes without tachypnea, rales, or rhonchi. There was neither cervical nor peripheral adenopathy, and no hepatosplenomegaly.
The results of the following laboratory tests were normal: hemoglobin level; total and differential white blood cell counts; sweat chloride test; α1-antitrypsin levels; IgE and allergy skin tests; and coccidioidin serologic and skin test. Results of a 5-TU purified protein derivative skin test were originally negative, but they showed a 9-mm induration in testing three months after the onset of symptoms.