Nasal sputum cytology reveals eosinophilia

A 35-year-old woman presents to an outpatient clinic during winter for persistent rhinorrhea. Nasal sputum cytology reveals eosinophilia. This finding is most characteristic of which of the following potential causes of this patient’s complaint?

  1. Vasomotor rhinitis
  2. Infection
  3. Allergic rhinitis
  4. Perennial non-allergic rhinitis
  5. Cold-weather associated rhinorrhea

View Explanation

Of the conditions listed, allergic rhinitis is most likely to be associated with nasal eosinophilia.

The finding of nasal eosinophilia is sensitive for allergic rhinitis but is not specific. Other causes of nasal eosinophilia include nasal polyps and a condition known as non-allergic rhinitis with eosinophilia. Other common causes of rhinitis, such as infection and vasomotor rhinitis, do not demonstrate nasal eosinophilia.

Quillen et al. report that allergic rhinitis can be distinguished from the numerous other types of non-allergic rhinitis with a thorough history and physical examination. Further testing, such as percutaneous skin testing and radioallergosorbent testing are only indicated in ambiguous cases.

Ahmadiafshar et al. investigated the use of the nasal smear examination for detecting eosinophilia in patients with allergic rhinitis. They examined 50 patients with allergic rhinitis compared to 50 matched patients without allergic rhinitis. The sensitivity, specificity, positive predictive value, and negative predictive value of this test were 74, 90, 88, and 77%, respectively. Consequently, nasal eosinophilia is highly specific and moderately sensitive in diagnosing allergic rhinitis.