Epithelial alterations arising from moderate nasal allergy to house dust were examined and compared to findings in epithelia from nonallergic controls. Biopsy specimens were taken during natural allergen exposure from two different sites: 1) the anterior tip of the inferior turbinate and 2) 2 cm behind it. The tissues were examined by both electron and light microscopy. In the allergic group, epithelial damage was found to be remarkable in the anterior nasal mucosae, where nonciliated cells were prevalent, but minor in the posterior nasal mucosae comprising ciliated and goblet cells. In the anterior nasal mucosae, conspicuous intercellular edema, epithelial shedding, and clusters of eosinophils in the epithelial layer were observed, whereas only a little epithelial shedding and edema in the basal area of the epithelium was noted in the ciliated areas. In controls, pathologic changes were not observed, although a little epithelial shedding was seen in the anterior turbinate. Although there are arguments for and against epithelial shedding in nasal allergy, this study confirms its presence even in patients with moderate allergy.