ABSTRACT
PURPOSE: Most patients suffer from croup only once in a life time. However, a small group of patients suffer from it several times. A type of croup from which they suffer more than 3 times is called recurrent croup. The cause of recurrent croup has not been clearly described, but in recent years the allergic reaction is considered as a cause of recurrent croup. ECP is one of the 4 major basic proteins of eosinophil, means eosinophil activation, and has been reported as a clinical indicator of bronchial asthma and other an allergic diseases. We measured serum ECP levels in recurrent croup patients in order to evaluate the roles of ECP as a diagnostic tools and eosinophil activation as part of the pathophysiology of recurrent croup. METHODS: 25 patients with 1st croup episode were enrolled in the study between April and August 1994. We phoned the 22 patients if they had ever caught any respiratory and allergic diseases including croup about 2 years since their discharge from the hospital. Three patients could not be connected. We divided these patients into two groups according to the recurrent rate of attack after discharge. The patients with more than three times of episode were diagnosed as recurrent croup patients, and others with one time of episode were diagnosed as single croup patients. The patients with two times episode were dropt out. Non-allergic 10 patients of the same age with acute viral enteritis were enrolled as a control group. Blood sampling was done at admission. Serum ECP levels were measured by ECP radioimmunosorbent assay kit (Phamarcia, Sweden). RESULTS: 1) Recurrent croup (n=9): The ECP level was 52.1+/-17.3 g/L. Single croup (n=12): The ECP level was 11.6+/-7.0 g/L. Control (n=10): The ECP level was 6.3+/-3.2 g/L. 2) There was no meaningful difference between the control and the single croup patients (p>0.05). 3) There was a meaningful difference between the control and the recurrent croup patients (p<0.05). 4) There was a meaningful difference between the single croup and the recurrent croup patients (p<0.05). 5) There was a linear correlation between eosinophil count and serum ECP levels (r=0.63, p<0.01). 6) For 2 years after discharge, pneumoniae was developed in 2 single croup patients. The recurrent rate of croup was 3-6 times in recurrent croup patients. Asthma was developed in 4 recurrent croup patients. And bronchiolitis was developed in 2 recurrent croup patients. CONCLUSIONS: The investigation of serum ECP levels enables us to distinguish recurrent croup patients from single croup patients. It suggests that eosinophil activation may play an important role in the pathophysiology of recurrent croup.