Nasal smear eosinophilia for the diagnosis of allergic rhinitis and eosinophilic non-allergic rhinitis.
OBJECTIVE
To evaluate nasal smear eosinophilia for the diagnosis of allergic rhinitis and eosinophilic non-allergic rhinitis in general practice.


METHODS
Nasal smear eosinophilia was assessed and compared with 'consensus diagnoses' made by three experts in a modified Delphi method.


METHODS
Nineteen general practices in The Netherlands.


METHODS
363 consecutive patients aged 12 years or over who visited their general practitioner because of chronic or recurrent nasal symptoms between 1 March 1990 and 1 March 1991.


METHODS
The predictive value of nasal smear eosinophilia for allergic rhinitis; the prevalence of eosinophilic non-allergic rhinitis.


RESULTS
The positive predictive value of nasal smear eosinophilia (> or = 10% eosinophils) for allergic rhinitis was 30/37 = 81% (95% confidence interval (CI): 65-92%), the negative predictive value 172/312 = 55% (95% CI: 50-61%). Addition of the result of nasal smear eosinophilia to the information that was already obtained from the medical history resulted in a significant but very small improvement in the discrimination between patients with and without allergic rhinitis. The prevalence of eosinophilic non-allergic rhinitis was 7/349 = 2.0% (95% CI: 0.8-4.1%).


CONCLUSIONS
Nasal smear eosinophilia contributes significantly to the diagnosis of allergic rhinitis; however, this contribution is very small and considered clinically irrelevant. Eosinophilic non-allergic rhinitis has a low prevalence; identifying this disorder is of minor importance. In conclusion, nasal smear eosinophilia is not recommended for use in general practice.
Crobach
M
M
Department of General Practice, Leiden University, The Netherlands.
Hermans
J
J
Kaptein
A
A
Ridderikhoff
J
J
Mulder
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D002648:Child; D003697:Delphi Technique; D004802:Eosinophilia; D004804:Eosinophils; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000276:immunology; D015995:Prevalence; D012220:Rhinitis / Q000175:diagnosis* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity