Nasal polyps: the relationship to allergy, sinonasal infection and histopathological type.

OBJECTIVE: To evaluate the relationship of nasal polyps to allergy, sinonasal infection and histopathological type by examining the prevalences of these factors among nasal polyps patients.

STUDY DESIGN: Prospective descriptive study.

MATERIAL AND METHOD: A total of 73 patients were enrolled between October 1st, 1999 and August 31st, 2002 at the Allergy and Rhinology Clinic, Faculty of Medicine, Songklanagarind Hospital. The medical history was recorded. Allergy skin prick test, nasal endoscopy with biopsy and plain film paranasal sinus were performed. Positive allergy skin test was defined by at least 1 aeroallergen with a wheal size > or = 3 mm greater than the negative control. Rhinosinusitis was diagnosed by clinical symptoms, positive nasal endoscopy and/or positive plain film paranasal sinus. Histopathological investigation was classified as eosinophil- or neutrophil-dominated inflammation.

RESULTS: 68.5 per cent of patients with nasal polyps had a positive allergy skin test, 67.1 per cent had rhinosinusitis. Eosinophil-dominated inflammation was presented in 69.9 per cent and neutrophil-dominated inflammation in 30.1 per cent, respectively. Within each histopathological type, 62.7 per cent of patients with eosinophil-dominated inflammation and 81.8 per cent of patients with neutrophil-dominated inflammation had a positive allergy skin test. There was no statistically significant difference in prevalence of positive allergy skin test between eosinophil- and neutrophil-dominated inflammations (p = 0.107). 60.8 per cent of patients with eosinophil-dominated inflammation and 81.8 per cent of patients with neutrophil-dominated inflammation had rhinosinusitis. There was no statistically significant difference in prevalence of rhinosinusitis between eosinophil- and neutrophil-dominated inflammations (p = 0.079).

CONCLUSION: Nasal polyps had association with positive allergy skin test (68.5%), rhinosinusitis (67.1%) and eosinophil-dominated inflammation (69.9%). There were no statistically significant differences in prevalence of positive allergy skin test and rhinosinusitis between eosinophil- and neutrophil-dominated inflammations (p = 0.107 and p = 0.079, respectively).