Nasal eosinophilia in allergic and nonallergic rhinitis: usefulness of the nasal smear in the diagnosis of allergic rhinitis

R, C.R.K. B, N. R. A Study on the Significance of Nasal Smear Eosinophil Count and Blood Absolute Eosinophil Count in Patients with Allergic Rhinitis of Varied Severity of Symptoms

Introduction: Rhinitis is defined as inflammation of nasal mucosa. Allergic rhinitis is the most common type of chronic rhinitis with increasing prevalence. Tests such as nasal smear for eosinophilia, Skin prick test, Serum absolute eosinophil count and Immunoglobulin IgE helps us in diagnosis of allergic rhinitis. Objective: To evaluate the efficacy of the nasal smear for eosinophilia and blood absolute eosinophil count tests to diagnose allergic rhinitis in patients with varied severity of symptoms. Materials and methods: In this prospective study, all patients above 12 years of age with symptoms suggestive of allergic rhinitis were enrolled in our study. Severity assessment was done by visual analog scoring and Total nasal outcome scoring. Diagnostic nasal endoscopy with nasal smear for eosinophilia, complete blood count and blood absolute eosinophil count tests were done. Results: A total of 60 patients were enrolled in the present study. Age ranged from 13 to 55 years with female preponderance. The most common symptom was rhinorrhea found in 100% of study population, followed by sneezing present in 57 (93.5%) patients. 10 out of 12 patients with mild intermittent symptoms had < 5% of eosinophil elicited in nasal smear and 2 patients had negative smear of eosinophils. Only 13% had mild eosinophilia. In this study, in those patients with mild intermittent symptoms neither nasal smear eosinophilia nor Blood absolute eosinophil count was found to be significant. Conclusions: Nasal smear cytology and blood absolute eosinophil count were found to be significant only in patients with moderate-severe symptoms. Those patients with mild intermittent symptoms need not be tested as it will be insignificant. In these patients, we must rely on the visual analogue score based on the severity of symptoms rather than laboratory tests.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03945-5.

Study the Role of Nasal Scrap Cytology in Allergic Rhinitis Patients in Rural Population

Allergic Rhinitis is one of the gift of modern era. Condition is involving wide range of age group starting from children to old age people. In spite of latest diagnostic facility and advanced treatment, it is still a great challenge for the otorhinolaryngologist. This study was done to perform simple and cost effective test to understand the severity of Allergic Rhinitis. To investigate the patients of allergic rhinitis with specific focus on nasal scrape cytology. After applying inclusion and exclusion criterion were found suitable and hence selected for the present study. 100 patients who were clinically diagnosed on history and examination as allergic rhinitis were included as cases while control group consisted of 100 subjects having no symptoms of allergic rhinitis. These patients were a subjected to nasal scrape cytology for which Cytobrush Plus (Medscand Cell Sampling Kit), Malmo, Sweden, was employed. Mucosal specimens were acquired by scraping the surfaces of the middle thirds of inferior turbinates with Cytobrush Plus (Medscand Cell Sampling Kit), Malmo, Sweden. The samples thus obtained were transferred onto glass slides to be fixed in 95% ethyl alcohol and stained with May Gurwald Gimesa stain to study pattern and profile of different types of cells like eosinophils, goblet cells, mast cells. The nasal eosinophils were studied under 1000 × magnification of light microscope 10-well spread, high power epithelium fields were examined and the quantitative score of nasal eosinophils was rated according to a scale described by Meltzer. In study group all 100 patients underwent nasal scrape cytology. 25 (25%) patients in study group showed grade 1 + nasal eosinophilia followed by grade ½ + in 24 (24%), grade 0 in 22 (22%) and grade 2 + in 21 (21%). In control group 80% of subjects had grade 0 nasal eosinophilia. Difference between nasal eosinophilia in the study and the control group were found to be statistically significant. In study group 54% showed grading > 0.5 + whereas 46% showed ≤ 0.5 + . The sensitivity and specificity were observed to be 54% and 100% respectively. The results thus found were statistically significant. Nasal scrape cytology which was an added dimension proved to be a more specific than sensitive test. The specificity of nasal scrape cytology in our study was 100%. Sensitivity was only 54%. 22% of the patients of allergic rhinitis showed an eosinophil count more than 300/cu mm.

Nasal eosinophilia and eosinophil peroxidase in children and adolescents with rhinitis

Background

Researchers have shown that eosinophil peroxidase (EPO) is a relatively accurate marker of eosinophilia and eosinophil activity. However, its use as a marker of eosinophilic inflammation in nasal secretions is limited because the diagnostic cutoff values of EPO for use as a one-time test for allergic diseases such as allergic rhinitis have not been established.

Purpose

To identify the correlation between nasal eosinophil count and EPO in children and adolescents with rhinitis.

Methods

We recruited patients <18 years of age with rhinitis for more than 2 weeks or more than 2 episodes a year whose nasal eosinophil and EPO were measured at a single allergy clinic. The eosinophil percentage was calculated by dividing the eosinophil count by the number of total cells under light microscopy at ×1,000 magnification. EPO and protein were measured from nasal secretions. We retrospectively analyzed the correlation between nasal eosinophils and protein-corrected EPO (EPO/protein) value.

Results

Of the 67 patients enrolled, 41 were male (61.2%); the mean age was 8.2±4.0 years. The median nasal eosinophil count was 1 and percentage was 1%. The median protein-corrected EPO value was 12.5 ng/μg (range, 0–31 ng/μg). There was a statistically significant correlation between eosinophil count and percentage (P<0.001). However, the eosinophil percentage and EPO did not correlate. The eosinophil count and EPO had a statistically significant correlation (P =0.01). The EPO cutoff value examined for nasal eosinophil counts of 2, 5, 10, and 20 was 17.57 ng/μg regardless of the reference count. The largest area under the curve value was obtained when the receiver operating characteristic curve was drawn using the eosinophil count of 2.

Conclusion

Nasal eosinophil count was significantly associated with protein-corrected EPO.

Nasal eosinophilia in nasal smears of patients with persistent and intermittent allergic rhinitis

BACKGROUND

Eosinophils are the principal effector cells involved in the pathogenesis of allergic rhinitis. Cell numbers increase in non-allergic rhinitis patients with eosinophilia, aspirin hypersensitivity and nasal polyposis, as well as in allergic rhinitis patients. Exfoliative nasal cytology can be used in the differential diagnosis of allergic rhinitis.

OBJECTIVE

To evaluate nasal eosinophilia in nasal smears of patients with mild, persistent and intermittent allergic rhinitis.

METHODS

The study comprised 60 patients with allergic rhinitis and 20 healthy volunteers. The patients were divided into intermittent and persistent allergic rhinitis groups. Nasal smear status, eosinophil numbers and Total Nasal Symptom Scores were compared.

RESULTS

Nasal smear results were pathological in 40 of 60 allergic rhinitis patients, which was significantly higher than the rate in controls. The mean nasal eosinophilia score was significantly higher in the intermittent allergic rhinitis than in the persistent allergic rhinitis group (p = 0.029). There was a positive correlation between nasal eosinophilia score and Total Nasal Symptom Score (r = 0.652; p < 0.05) in persistent allergic rhinitis and intermittent allergic rhinitis patients.

CONCLUSION

The nasal smear test is inexpensive, objective and simple to perform, and should be part of the diagnostic investigation.

Recent advances in the diagnosis of allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is a disorder with high prevalence worldwide. Identification of clinically relevant allergens is the key step for the diagnosis, allergen avoidance and allergen specific immunotherapy for AR. Areas covered: With the new findings of mechanisms of AR and the development of technology, much progress has been achieved in the diagnosis of AR recently. We review the recent advances about local IgE, in vivo and in vitro tests, cytological diagnosis and nitric oxide (NO) in the diagnosis of AR. Expert commentary: AR is traditionally diagnosed with the combined evaluation of history and allergen sensitization by in vivo skin prick tests and in vitro allergen specific IgE in serum, to confirm the correlation between clinical history and potential allergens. Nasal provocation test and local IgE measurement can be used to diagnose local AR. Allergen microarray has the ability to detect more potential allergens. Basophil activation and mast cell activation tests can be used in allergen diagnosis and to modify the response to immunotherapy, while cytological diagnosis is useful in the differential diagnosis of AR and non-AR. Nasal NO has been confirmed to be an optimal biomarker to discriminate between AR and non-AR.

Tympanometric Patterns of Children with Allergic Rhinitis Treated at a Tertiary Health Institution

Objectives

To determine the prevalence of otitis media with effusion (OME) and compare patterns of tympanogram between children with and without allergic rhinitis in Ibadan, Nigeria.

Study Design

A case-control study of children (2-7 years) with AR from May 2015 to March 2016.

Setting

Tertiary hospital.

Subjects and Methods

Consecutive 86 children with AR and 86 healthy controls (nonallergic) participated in the study. A structured questionnaire was administered to parents or caregivers of the participants to obtain relevant sociodemographic and clinical information. Diagnosis of AR was by symptomatology and nasal cytology. Both groups had ear, nose, and throat examination and tympanometric evaluation. OME was diagnosed according to Jerger’s tympanometric patterns.

Results

The mean ± SD ages of cases and controls were 3.80 ± 1.72 and 3.78 ± 1.71 years, respectively. All cases presented with watery nasal discharge, bouts of sneezing, and nasal itching. The duration of AR symptoms was 18 ± 13 months. Among cases and controls, Jerger’s type A tympanogram was the most common pattern, while type C was the least common. Thirty-nine (45.3%) children with AR had OME, as compared with 8 (9.3%) controls, and the difference was statistically significant (P < .001; odds ratio = 8.090; 95% CI = 3.48-18.79).

Conclusion

Prevalence of OME was significantly high among children with AR. Jerger’s type B and C tympanograms were more common among children with AR than the healthy pediatric population. This background information supports the need for routine tympanometric evaluation of children with AR.

Nasal Cytology as a Marker of Atopy in Children

The aim of this study was to evaluate the cytological picture of nasal mucosa in children with atopic diseases and to determine the diagnostic value of the test for the diagnosis of atopic diseases. The study included 140 children from 4 months to 17 years old. Among children with a history of atopy, there were 30 children with atopic dermatitis, 30 children with asthma, and 46 children with allergic rhinitis. The control group consisted of 34 healthy children. The nasal scraping technique has been used to collect samples from the nasal cavity. The samples were evaluated under light microscope. Epithelial cells as well as infiltrating cells were assessed. The only statistically significant group of cells differentiating children with atopic disease and without atopy were eosinophils, which in children with atopy were significantly more common. Assuming a significant eosinophilia value of at least 5% of all cells in cytogram, the sensitivity of nasal cytology in allergic rhinitis was 52.2%, in asthma 33.3%, and in atopic dermatitis 13.3%. The specificity of the test in atopic diseases was 94.1%. It can be concluded that nasal cytology with eosinophilia assessment can be a useful tool for an early diagnosis of atopic disease in children.

Bronchial asthma control after argon plasma coagulation turbinectomy in patients with chronic rhinitis

Bronchial asthma is frequently accompanied by chronic rhinitis. It has been observed that effective treatment of rhinitis may reduce asthma symptoms. The aim of the study was the evaluation of the control of bronchial asthma symptoms in patients with chronic rhinitis after argon plasma coagulation turbinectomy (APCt). The effect of APCt was assessed in 47 adults with drug-resistant chronic rhinitis and bronchial asthma 3-month post-procedure. Changes of asthma symptoms were scored using Asthma Control Test (ACT). Subjective improvement of nasal congestion 3 months after APCt was observed in 87% and of rhinorrhoea in 75% patients. Rhinomanometry showed 219 ± 19 cm³/s increase of flow and 0.75 ± 0.06 Pa/cm³/s reduction of resistance. The prevalence of patients with insufficient bronchial asthma control decreased from 79 to 4%. The decrease was associated with diminished frequency of eosinophils >20% in nasal cytology from 83% pre-procedure to 28% in the follow-up. The percentage of eosinophils >20% in cytology before APCt increased the chance for asthma control improvement by 22.8 times. Reduction in symptoms of drug-resistant rhinitis after APCt is followed by significant improvement of asthma control. The most beneficial therapeutic effects of APCt are noted in patients with a high rate of eosinophils in nasal cytology.

Nasal mucosa temperature as a marker of disease in children with allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a symptomatic disorder of the nose induced after allergen exposure by an IgE-mediated inflammation of the nasal mucosa. This study was designed to investigate the role of nasal mucosa temperature in AR.

METHODS

We investigated the relationship between eosinophilic infiltration, nasal obstruction, and nasal mucosa temperature in 35 children with rhinitis aged 6-12 years.

RESULTS

A significant relationship was shown between nasal temperature values and eosinophil infiltration at nasal cytology (p < 0.01). Nasal temperature was also significantly associated with nasal obstruction, assessed in terms of nasal volume (Vol [2-5 cm]; p < 0.05) and minimum cross-sectional area (p < 0.01). No significant correlation emerged between the degree of nasal obstruction and presence of eosinophils at nasal cytology (p > 0.05).

CONCLUSION

These results suggest a relationship between nasal temperature and nasal mucosa inflammation and obstruction.

Nasal eosinophilia as a marker for allergic rhinitis: a controlled study of 50 patients

Eosinophils are the principal effector cells involved in the pathogenesis of allergic inflammation. We conducted a study to investigate the validity of the nasal smear examination for detecting eosinophilia in patients with allergic rhinitis. Our study group was made up of 50 patients with allergic rhinitis and 50 age- and sex-matched controls without allergic rhinitis. Smears were obtained from nasal secretions in both groups and then fixed, stained, and studied under light microscopy. Statistical analysis revealed that the odds ratio for eosinophilia positivity in nasal smears in the rhinitis group was 25.61 with a 95% confidence interval of 8 to 78. The sensitivity, specificity, positive predictive value, and negative predictive value of this test were 74, 90, 88, and 77%, respectively. We conclude that the nasal eosinophilia test is highly specific and moderately sensitive in diagnosing allergic rhinitis, and that it therefore can be used as an easy, noninvasive, and inexpensive procedure for screening patients and for conducting epidemiologic studies of this disorder.

Correlation of routine examinations for the diagnosis of house dust mite allergic rhinitis

OBJECTIVE

To evaluate the correlation between the routine diagnostic tests for house dust mite (HDM) sensitization in Chinese allergic rhinitis (AR) patients, including the skin prick test (SPT), serum HDM-specific immunoglobulin E (sIgE) and nasal smear eosinophilia.

METHODS

The ImmunoCAP assay was employed to detect serum total IgE and sIgE. The SPT and nasal smear eosinophil counts were performed using standard procedures.

RESULTS

Of 82 subjects with HDM-related symptoms and positive SPT results, 55 individuals showed an sIgE level equal to or greater than CAP class 1 for both Dermatophagoides pteronyssinus (Der p) and D. farinae (Der f), and 62 individuals demonstrated positive eosinophils in nasal smears. sIgE of Der p and Der f presented a linear correlation, and the level of serum HDM-sIgE was also positively correlated with total IgE. An increasing sIgE level was correlated with higher SPT grades in both Der p and Der f. Meanwhile, the correlation coefficient exhibited an increase in value with aging, and the 31- to 40-year age group demonstrated the highest value for both Der p and Der f.

CONCLUSION

The positive correlation between SPT and sIgE reaction to HDM varied according to the age of patients with AR.

Correlation Between Eosinophilia and Nasal Features in Allergic Rhinosinusitis

A characteristic feature of nasal allergy is local accumulation of inflammatory cells, particularly mast cells and eosinophils, and their mediators, which have been implicated to be responsible for symptoms and signs of allergies. This prospective study tested the hypothesis that severity of nasal symptoms at presentation was related to the presence of nasal eosinophilia, using consecutive patients with allergic rhinitis attending the outpatient Department of Otorhinolaryngology, University College Hospital, Ibadan, Nigeria, between March and December 2008. Excluded were those who had commenced antihistamine and similar antiallergy drugs. Nasal eosinophilia, skin sensitivity, sinus radiograph, and clinical features were graded using standard classification. The study was composed of 49 subjects (28 males and 21 females). The subjects’ age ranged from 7 to 53 years (mean ± SD: 28 ± 4 years). Nasal eosinophilia and abnormal skin sensitivity response were seen in 41 (83.8%) and 37 (75.5%) subjects, respectively. Rhinorrhea, sneezing, and nasal obstruction constituted 42 (85.7%), 31 (63.3%), and 21 (42.9%), respectively, while inferior turbinate enlargement and radiological involvement were seen in 29 (59.2%) and 36 (73.5%) patients. The Spearman correlation test revealed a significant association between nasal smear eosinophilia and rhinorrhea (P = .008) and sneezing (P = .04), although there was no significant association with other variables. The authors conclude that the degree of nasal eosinophilia may be useful in predicting the severity of rhinorrhea and sneezing among the clinical features of nasal allergy.

Clinical Importance of Eosinophil Count in Nasal Fluid in Patients with Allergic and Non-Allergic Rhinitis

Eosinophil count in nasal fluid (ECNF) was used to differentiate nasal pathologies. Receiver Operating Characteristic (ROC) curve analysis and the area under the curve (AUC) were performed to evaluate the ECNF's accuracy in distinguishing allergic rhinitis (AR) from non-allergic rhinitis (NAR). We also evaluated the accuracy of ECNF in recognizing patients with mild and severe symptoms of rhinitis and patients with ineffective and effective clinical responses to antihistamines. 1,170 consecutive adult patients with a clinical history of rhinitis were studied. ECNF's median in AR was 6.0 and 2.0 in NAR and the best cut-off value was > 3.0, AUC = 0.75. ECNF's median in AR with mild nasal symptoms was 3.0 and 7.0 with severe symptoms, and the best cut-off value was 4.0, AUC = 0.90. ECNF's median in NAR with mild nasal symptoms was 2.0 and 8.5 with severe symptoms, and the best cut-off value was > 4.0, AUC = 0.86. ECNF's median in AR with effective clinical response to antihistamines was 4.0 and 8.0 with ineffective response, the best cut-off value was ≤ 5.0, AUC = 0.94. ECNF's median in NAR with an effective clinical response to antihistamines was 1.0 and 2.0 with ineffective response, and the best cut-off value was ≤ 3.0, AUC = 0.64. Our results suggest an interesting practical use of ECNF data as evaluator of the clinical severity both AR and NAR. As predictor of the clinical response to antihistamines, ECNF is accurate only in patients with AR. The ECNF's performance was moderately accurate in distinguish patients with AR and NAR.

Evaluation of nasal cytology in subjects with chronic rhinitis: a 7-year study

BACKGROUND

No diagnostic test had been specifically developed to diagnose nonallergic rhinitis (NAR). Also a negative nasal smear for eosinophils does not rule out the diagnosis. There is a significant diagnostic problem in patients with NAR. How can we solve this problem?

OBJECTIVES

Assessment of other cells than eosinophils present in the cytogram such as basophils, neutrophils, and goblet cells may help us to classify and management of diagnostic problem of rhinitis. We sought to characterize the cellular pattern of patients with allergic rhinitis (AR) and compare them with those of NAR.

METHODS

According to the skin prick test positivity or negativity, individuals were divided into AR and NAR groups, respectively. Allergic rhinitis group was further divided into seasonal, perennial, and mixed subgroups. Nonallergic rhinitis group was also divided into the following 5 subgroups according to the nasal smear cytologic result: basophilic, neutrophilic, eosinophilic, mixed, and nonallergic noninfectious type. So the frequency rates of the subgroups were calculated and also smear cytologic results were compared.

RESULTS

Frequency of AR was approximately equal to NAR in subjects with chronic rhinitis. Neutrophilic, eosinophilic, mixed, and nonallergic noninfectious types were the common types of NAR. An evident nasal eosinophilia was found in AR and eosinophilic NAR, whereas a higher percentage of goblet cells were determined in nonallergic noninfectious rhinitis. There is no significant difference between cytologic results from NAR and AR patients.

CONCLUSION

In the patient with positive skin test result, the presence of nasal eosinophilia strongly supports the diagnosis of AR. No diagnostic test had been specifically developed to diagnose chronic NAR. Also, a negative nasal smear for eosinophils does not rule out the diagnosis. Assessment of other cells present in the cytogram such as basophils, neutrophils, and goblet cells may also provide valuable information for differential diagnosis and management of these conditions.

Prevalence of allergic rhinitis and nasal smear eosinophilia in 11- to 15 yr-old children in Shiraz

Allergic rhinitis (AR) is a common condition among schoolchildren. The prevalence rate of AR differs among countries and even among regions within the same country. The objective of this study was to determine the prevalence of nasal symptoms and signs of AR and nasal smear eosinophilia in 11- to 15-yr-old children in Shiraz. A total of 4584 children aged 11-15 yr of both sexes were surveyed from May 1995 to April 1996, and nasal symptoms and signs of AR (sneezing, rhinorrhea, nasal blockage, itching, color change, mucosal swelling, nasal wetness, and nasal crease), based on questionnaire and ear, nose and throat (ENT) examination were recorded. In addition, smears were taken from nasal secretions and stained. The results compared with nasal smears related to 340 healthy children. 1008 (22%) schoolchildren had nasal symptoms of AR (based on the questionnaire), 445 (9.7%) were identified as having nasal symptoms and signs of AR (based on the questionnaire and ENT specialist examination), and 226 (5.8%) had nasal symptoms and signs of AR associated with nasal eosinophilia (based on the questionnaire, ENT specialist examination and positive nasal smear for eosinophilia). Nasal eosinophilia was present in 274 (62%) children with nasal symptoms and signs of AR. This survey showed that prevalence of nasal symptoms and signs of AR was high in schoolchildren in Shiraz. Nasal smear eosinophilia had a diagnostic specificity of 96% and sensitivity of 62% and seems to be a potentially valuable test for AR.

Diagnostic significance of nasal eosinophilia in allergic rhinitis

BACKGROUND

Nasal eosinophilia is one of the potential tests for substantiating the diagnosis of allergic rhinitis.

OBJECTIVE

The aim was to establish the validity of nasal eosinophilia in allergic rhinitis, to study it's various clinical correlates and interpret it in context of skin sensitivity pattern.

STUDY DESIGN

Prospective cased study.

SETTING

Hospital based.

PATIENTS

The patients were selected on the basis of history and clinical examination and were from the Himalayan region.

INTERVENTION

Diagnostic.

METHODS

The patients and the equal number of controls, were subjected to nasal smear for eosinophilia and intra-dermal skin tests to various allergeus.

RESULTS

Overall, eighty percent of nasal smears were positive in various degrees among the cases. Around eighty-eight percent of cases showed both smear and skin test positivity, thereby signifying a high degree of harmony among them and further validating and confirming the diagnosis of allergic rhinitis.

CONCLUSION

Nasal eosinophilia was found to be a useful diagnostic test in allergic rhinitis, with a moderately high sensitivity and a high specificity.

Peripheral eosinophilia in the diagnosis of chronic rhinosinusitis

PURPOSE

To determine the relationship between peripheral blood eosinophilia and chronic rhinosinusitis.

MATERIALS AND METHODS

A retrospective review was conducted of consecutive operative cases during 1 calendar year. The preoperative complete blood count (CBC) were tabulated for three groups of patients: those undergoing endoscopic sinus surgery, those undergoing septoplasty with turbinate reduction alone, and a nonrhinologic control group. Statistical analysis was performed to determine differences in the components of the CBC among these three groups of patients and to identify significant associations between abnormal peripheral eosinophil counts and these diagnoses.

RESULTS

A total of 87, 32, and 92 patients were identified for the endoscopic sinus surgery (ESS), septoplasty, and control groups, respectively. Significant differences in the percentages of eosinophils, lymphocytes, and neutrophils were noted among the three groups (P <.05). Comparison among groups indicated that ESS patients had significantly higher percent peripheral eosinophilia when compared with both the control group and septoplasty group (P <.001 and P =.010, respectively); no significant difference was noted between the septoplasty group and the control group (P =.627). The sensitivity and specificity of the peripheral eosinophil count for chronic sinusitis were 49.4% and 84.7%, respectively.

CONCLUSIONS

The peripheral eosinophil count in chronic sinusitis is elevated compared with both a nonrhinologic control group and a group of patients with septal deviation. Furthermore, abnormally elevated eosinophil counts are associated with chronic sinusitis but not chronic rhinitis alone. However, this association is not strong enough to be used in the diagnosis of chronic sinusitis because of poor sensitivity.

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.

DESIGN

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

SETTING

Nineteen general practices in The Netherlands.

SUBJECTS

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.

MAIN OUTCOME MEASURES

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%).

CONCLUSION

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.