Diagnostic significance of impression cytology in allergic rhinoconjunctivitis

Impression Cytology (IC) is a noninvasive and easily repeated technique for investigating many pathologies of the conjunctiva such as dry eye, drug toxicities, and melanoma. In addition to skin tests and determination of serum IgE levels, the presence of eosinophilia in the nasal mucosa and the conjunctiva is an important diagnostic factor in allergic rhinoconjunctivitis. Eosinophilia can classically be shown by the nasal smear technique as well as IC. The nasal smear is a difficult test to carry out and does not always give adequate results. With this in mind, we collected cells from the nasal mucosa and superior palpebral conjunctiva from 27 patients with allergic rhinoconjunctivitis (17 female, 10 male) using 5 x 5 mm, 0.22 micron pore-sized cellulose acetate paper. The specimens were fixed in 95% alcohol and were then stained with hematoxylin eosin and periodic acid-Schiff stain for examination by light microscopy. Taking the free and intraepithelial eosinophilia into consideration, the specimens were grouped. Of all patients, 92.6% and 85.2% had nasal and conjunctival eosinophilia, whereas 44.4% and 25.9% had nasal and conjunctival mononuclear cells, respectively. Our study has shown that IC is a very reliable and practical technique that offers a valuable alternative test for investigating both the intraepithelial and free eosinophilia in allergic rhinoconjunctivitis and other pathologies that cause cytologic changes.