False-colour scanning electron micrograph (SEM) of human nasal mucosa in allergic rhinitis. Caused by an allergy to pollen, this inflamed mucosa shows its ciliated (hairy) surface overgrown in patches. Cilia are common on the epithelium of the respira- tory tract, where their beating serves to remove particles of dust, pollen, and other foreign material. Here, an allergy to pollen has resulted in the cilia lengthening. Symptoms may include nasal congestion; itching of nose, throat & eyes; and hay fever. Allergic rhinitis can be treated with anti-histamine drugs, and pollen desensiti- zation. Magnification: x4,000 at 6x7cm size.