The significance of nasal eosinophils and mast cells in children with nasal symptoms.

Nasal smears from children with symptoms of nasal obstruction and/or discharge were examined for the presence of eosinophils, mucus-containing cells and mast cells. The presence of more than one eosinophil or any mast cells was significantly associated with atopy as determined by immediate hypersensitivity on skin prick testing. Twelve children with markedly increased numbers of nasal smear mast cells are described. In these children symptoms frequently commenced in the first 6 months of life. Nasal eosinophilia was not noted in any of the cases. Nasal smear mastocytosis was associated with significant perennial symptoms and would be missed if nasal smears are examined only for eosinophilia.