A study of eosinophil count in nasal and blood smear in allergic respiratory diseases in a rural setup.
Abstract: Allergic respiratory disorders are fairly common visiting cases in pediatrics outpatient department (OPD). With an appropriate history and detailed examination, diagnosis may not be problematic. Routine investigation may not contribute much to the final diagnosis but may help in ruling out other possibilities. This study was done to evaluate sensitivity and specificity of blood or nasal eosinophilia in subjects suffering from allergic respiratory disorders and also to assess the feasibility of nasal cytogram which is a simple, economical and reliable investigation in allergic respiratory disorders. This is a prospective clinical correlation study of patients attending outpatient department. 100 subjects aged between 2-18 years of either sex were selected for the estimation of eosinophil count in nasal and peripheral smear in allergic respiratory disorders. All allergic respiratory cases based on eosinophillia. The nasal and blood eosinophilia were compared with each other and clinical findings of allergic rhinitis with or without asthma were studied. In this study peak age incidence was seen between 11-18 years and it was more common in males. Rhinorrhoea, pale mucosa and nasal obstruction were common findings in allergic rhinitis with bronchial asthma. Nasal eosinophilia was seen in 52.4% and 64.9% of cases of allergic rhinitis and allergic rhinitis with asthma respectively. Blood eosinophilia was seen in 54% and 56.8% of cases of allergic rhinitis with asthma respectively. Nasal cytogram which is a simple, economical and non- invasive procedure can be used as an alternative to invasive peripheral smear eosinophilia as both are equally efficacious in diagnosing allergic respiratory diseases.

KEY WORDS: Eosinophilia; Allergic rhinitis; Bronchial asthma
Article Type: Report
Subject: Hay-fever (Risk factors)
Hay-fever (Research)
Asthma (Diagnosis)
Asthma (Care and treatment)
Asthma (Research)
Authors: Kumar, Naveen
Bylappa, Kiran
A.c., Ramesh
Reddy, Swetha
Pub Date: 01/01/2012
Publication: Name: Internet Journal of Medical Update Publisher: Dr. Arun Kumar Agnihotri Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2012 Dr. Arun Kumar Agnihotri ISSN: 1694-0423
Issue: Date: Jan, 2012 Source Volume: 7 Source Issue: 1
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: India Geographic Code: 9INDI India
Accession Number: 277601642
Full Text: INTRODUCTION

Hay fever (allergic rhinitis) and asthma are two very common allergic diseases of the respiratory tract (1). The two have much in common as to age at onset, seasonal manifestations, and causation. Hay fever involves the mucosa, or lining of the upper respiratory tract only, whereas asthma is confined to the bronchial tubes of the lower respiratory tract (2).

There is mounting evidence that eosinophils are implicated in pathophysiology of allergic respiratory diseases, the direct and easy access of airborne allergens and irritants to the airways stimulate mast cells to produce IgE and cytokines which serves as enhancing factors for eosinophilic infiltration in allergic diseases (3). Since allergic rhinitis and asthma are such prominent disorders of immediate hypersensitivity, it is not surprising that identification of eosinophil leukocytes within the nasal and bronchial mucosa and corresponding eosinophilia of the nasal secretion and sputum are common findings in atopic populations (4).

In the geographical area where allergens are prevalent, their role as the etiological factor is higher in allergic respiratory disorders (5). Confirmation of allergen as etiologic agent is difficult in a small setup, where IgE estimation and allergy tests are not accessible (6).

This study was done to evaluate sensitivity and specificity of blood or nasal eosinophilia in subjects suffering from allergic respiratory disorders and also to assess the value of nasal cytogram as an alternative investigation.

METHODOLOGY

This was a prospective clinical correlation study conducted from 2008 to 2010, of 100 children between 2 to 18 years of either sex, with typical history and clinical features of allergic respiratory diseases who attended the outpatient department of Pediatrics. Children with tuberculosis, recurrent and chronic pneumonia, malnutrition, malignancy, collagen vascular disorders and those who were on steroid therapy were excluded from the study. The history, clinical features and investigation were noted in a proforma specially designed for the study. The following investigations were done: blood studies, nasal discharge smear for eosinophil count, Mantoux test and chest X-ray in all children included in the study. Consents from the parents and institutional ethical committee clearance were obtained.

Nasal and peripheral smear examination was done as follows:

Nasal Smear Preparation

Nasal secretion was collected by asking the child to blow his nose into a plastic wrap and then placed on a glass slide. If he was too young to do this or insufficient secretion was obtained, cotton tipped swab was inserted into a nostril and left for 60 seconds. The nasal secretion which was obtained was transferred onto a glass slide, teased out and allowed to air dry.

Blood Studies

With strict aseptic precautions, blood sample was drawn by venepuncture and 3 ml of blood was collected in Ethylene Diamine Tetra Acetic Acid (EDTA) anticoagulant. The sample collected was subjected to investigations like Hb%, Total Count (TC), Differential Count (DC), Erythrocyte Sedimentation Rate (ESR), Absolute eosinophil count (AEC), and peripheral smear examination.

Peripheral smear preparation

A small drop of blood was placed about 1 or 2 cm from one end of a pre-cleaned slide and immediately another slide with a pre-cleaned edge was placed at an angle of 25 degrees and moved backwards to make contact with the drop. The drop of blood was spread quickly along the line of contact of spreader with the slide and allowed to air dry. Peripheral blood smear was studied using Leishman's stain whereas nasal smear was studied by Haematoxylin and Eosin (H & E) stain.

Statistical Analysis

The following methods of statistical analysis have been used in this study, Chi-square test Student "t" test, Sensitivity, specificity positive predictive value, negative predictive value. Data analysis was carried out using Statistical Package for Social Science (SPSS Ver. 10.5).

RESULTS

A total of 112 patients presented to outpatient department of paediatrics during the study period with history suggestive of allergic rhinitis. 12 of them were excluded from the study because of associated malnutrition, pneumonia, tuberculosis or steroid therapy. The results of analysis of data of 100 study cases were as follows. 35% of the allergic respiratory cases were in the age group>15 years, among this 63% of the cases were of adolescent group (aged between, 11-18 years). The incidence of allergic disorder was more common in males (62%) compared to females (38%). Female: Male Ratio= 1:1.6 (Table 1a & b).

In this study dust was the most common risk factor for allergic rhinitis accounting for 81% followed by weather changes 62%, whereas in allergic rhinitis with bronchial asthma, weather change is a common risk factor accounting for 94%, followed by dust (73%) and family history (64%) (Table 2). In this study the most common sign and symptom was rhinorrhoea (100%) in both the groups followed by nasal obstruction (81%) (Table 3) The mean nasal eosinophil in allergic rhinitis (20.10 cells) and bronchial asthma (20.19 cells) were almost similar, and the mean blood eosinophil count in allergic rhinitis with asthma (589) was higher than in allergic rhinitis (506) but this was statistically not significant (p=0.270) Table 4. In this study all 100 cases were investigated for both nasal and blood eosinophil count. The positive nasal eosinophilia (>10cells) cases were 57%. Similarly, the positive blood eosinophilia (>440 cells/cc mm) were 55%. Nasal eosinophilia is more common in allergic rhinitis with asthma compared to only allergic rhinitis (64.9 vs. 54.5) but this was statistically not significant (p>0.223) Table 5a. Blood eosinophilia is almost similar in allergic rhinitis with asthma compared to only allergic rhinitis (56.8 vs. 54.0) but statistically not significantly (p>0.787) (Table 5b).

In this study we compared the correlation between nasal smear and peripheral blood eosinophils in allergic rhinitis patients with or without asthma. There was a positive correlation between nasal and peripheral blood smear eosinophilia in allergic rhinitis patients with asthma (Table 6a). Children with only allergic rhinitis had significant nasal eosinophilia showing that nasal smear eosinophilia is more reliable in this group (Table 6b).

The sensitivity of nasal eosinophilia is higher in allergic rhinitis with bronchial asthma compared to other group (85.7 vs. 73.5) (Table 7).

DISCUSSION

Allergic respiratory disorders are fairly common cases in pediatrics outpatient department (OPD). With an appropriate history and detailed examination the diagnosis is usually not

problematic. Routine investigations may not contribute much to the final diagnosis but may help in ruling out other possibilities. To confirm the allergic nature of the disease complicated tests like IgE, skin tests, (RAST) Radio Allergosorbent Test, (ELISA) Enzyme Linked Immuno Sorbent Assay etc, may not be possible in many hospital setups. Hence, a simple test for finding out allergy as an etiological agent by doing eosinophils count in nasal and peripheral blood smear and establishing it as a reliable and simple investigation has been tried.

In this study, majority of the allergic respiratory cases visiting paediatric OPD were of adolescent age group (11-18 years) accounting for 63% with male predominance. This finding was supported by Mirsaid Ghazi et al (7), who showed in their study that the incidence of allergic rhinitis in children increases with age and there was male predominance. The most common associated factor in patients with allergic rhinitis without bronchial asthma was dust exposure accounting for 81%, followed by weather change (62%); whereas in patients of allergic rhinitis with bronchial asthma weather change was the most common associated factor accounting for 94% followed by dust in 73% and family history in 64% of patients. Among 100 children, 49 had a family history of allergic respiratory disorder out of which bronchial asthma cases were significantly more, accounting for 64.8% and this is comparatively more than the observation made by Chowdary et al (50%) (8). Among other risk factors, food allergy and pet animal history was found in 27% and 18% of patients respectively. This observation was higher when compared to the study of Pokharel et al (6% and 12%) (9).

In this study, all the children with allergic rhinitis had rhinorrhoea (100%) which is also high in other studies done by Akbari et al10 and Mirsaid Ghaz et al (7) (92% and 73.4%). Pale mucosa is the next common clinical finding accounting for 84% which is similar to Akbari et al (10) accounting for 88%. Following this, nasal obstruction and sneezing were the next presenting finding. Among all clinical findings, symptoms contributed more than signs to the diagnosis.

Nasal eosinophil and blood eosinophil count was done in all (100) cases and nasal eosinophil count of >10 cells were considered as positive as per IAP text recommendation (11). Many studies have taken different cut-off values. Sanil et al (12) and Crobach et al (13), etc have considered >10 cells as significant similar to the present study. Similarly, blood eosinophil count >440 cell/cumm is considered as significant and this cut-off value is also considered by Chowdary et al (8).

Various workers have found varying results for nasal smear eosinophilia, ranging from 18% to 81%. This study correlates well with Sanil et al (57%)12. The mean absolute number of blood eosinophils in both groups totaling 100 patients was 537.07/cu mm and the mean value for eosinophils in the nasal secretions was (20.13.) When compared with both the groups the children with allergic rhinitis with asthma showed slightly higher blood eosinophils (588.9/cumm) than those with allergic rhinitis alone (506.6), which was similar to Saracli et el (14). However this difference was not statistically significant. Correlation between nasal smear and peripheral blood eosinophils in allergic rhinitis patients with or without asthma showed that out of 45 cases with AEC counts less than 440/cu mm, 16 (28.1%) showed increased nasal eosinophils. Whereas 55 children with AEC counts more than 440/cu mm, 41(71.9%) showed increased nasal eosinophils. Thus, there is positive correlation between nasal and peripheral blood smear eosinophilia. In children having only allergic rhinitis (63 cases), 33 showed significant nasal eosinophilia (>10/HPF), of which 25 (75.8%) showed increased peripheral smear eosinophils.

Out of 34(54%) cases which had blood eosinophilia >440/cu mm, of which 25 (73.5%) patients showed nasal smear eosinophilia >10 cells. In 63 children having allergic rhinitis with bronchial asthma, 26(70.3%) showed positive nasal eosinophilic count, of which 18 (69.2%) had peripheral smear eosinophilic count. Out of 21 (56.8%) cases with peripheral smear eosinophilia 18 (85.7%) showed nasal smear eosinophila. Hence, nasal smear eosinophila was more reliable in this group.

CONCLUSION

We like to conclude that peripheral eosinophilia contributes equally in diagnosing allergic rhinitis and bronchial asthma, whereas nasal eosinophilia contributes more in diagnosing bronchial asthma than allergic rhinitis. In children with allergic rhinitis with or without bronchial asthma, there is positive correlation between nasal and peripheral smear eosinophilia.

Hence, nasal cytogram which is a simple, economical and non-invasive procedure can be used as an alternative to invasive peripheral smear eosinophilia as both are equally efficacious in diagnosing allergic respiratory diseases.

REFERENCES

(1.) Porter P, Polikepahad S, Qian Y, et al. Respiratory tract allergic disease and atopy: experimental evidence for a fungal infections etiology. Med Mycol. 2011 Apr;49 Suppl 1:S158-63.

(2.) Bhattacharyya N, Kepnes LJ. Additional disease burden from hay fever and sinusitis accompanying asthma. Ann Otol Rhinol Laryngol. 2009 Sep;118(9):651-5.

(3.) Bloemen K, Verstraelen S, Van Den Heuvel R, et al. The allergic cascade: review of the most important molecules in the asthmatic lung. Immunol Lett. 2007 Oct 31;113(1):6-18.

(4.) Amorim MM, Araruna A, Caetano LB, et al. Nasal eosinophilia: an indicator of eosinophilic inflammation in asthma. Clin Exp Allergy. 2010 Jun;40(6):867-74.

(5.) Schwartz DA. Gene-environment interactions and airway disease in children. Pediatrics. 2009 Mar;123 Suppl 3:S151-9.

(6.) Shinogi J, Majima Y, Takeuchi K, et al. Quantitative cytology of nasal secretions with perennial allergic rhinitis in children: comparison of noninfected and infected conditions. Laryngoscope. 1998 May;108(5):703-5

(7.) Mirsaid Ghazi B, Imamzadehgan R, Aghamohammadi A, et al. Frequency of allergic rhinitis in school-age children (7-18 Years) in Tehran. Iran J Allergy Asthma Immunol, 2003 Dec;2(4):181-4.

(8.) Chowdary VS, Vinaykumar EC, Rao JJ, et al. A study of serum IgE and eosinophils in respiratory allergy patients. Indian J Allergy Asthma Immunol. 2003;17(1):21-4

(9.) Pokharel PK, Pokharel P, Bhatta NK, et al. Asthma symptomatics school children of Sonapur. Kathmandu Univ Med J (KUMJ). 2007 Oct-Dec;5(4):484-7.

(10.) Akbari H, Fana-Hosseini R, Miri S, et al. The prevalence of allergic rhinitis among 11-15 years old children in Shiraz. Iranian J Immunol. 2004;1(2):133-7.

(11.) Atkins D, Donald ML: Diagnosis of allergic disease. Nelson text book of pediatrics; 19th edition: 2010:741-51.

(12.) Sanil A, Aydin S, Ates G, et al. Comparison of nasal smear eosinophilia with skin prick test positivity in patients with allergic rhinitis. Kulak Burun Bogaz Ihtis Derg. 2006;16(2): 60-3.

(13.) Crobach M, Hermans J, Kaptein A, et al. Nasal smear eosinophilia for the diagnosis of allergic rhinitis and eosinophilic nonallergic rhinitis. Scand J Prim Health Care. 1996 Jun;14(2):116-21.

(14.) Saracli T, Scott RB. Comparative study of simultaneous blood and nasal secretion eosinophilia in children with allergic diseases. J Asthma Res. 1967 Mar;4(3):219-27.

Naveen Kumar * MD, Kiran Bylappa ([PSI]) ([dagger]) MS, Ramesh AC ([double dagger]) MD and Swetha Reddy ** MBBS

* Assistant Professor, Department of Pediatrics, Sri Devarj Urs Medical College & Hospital. Tamaka, Kolar, Karnataka, India

([dagger]) Assistant Professor, Department of Otorhinolaryngology, Sapthagiri Institute of Medical Sciences & Research Center, Bengaluru, Karnataka, India

([double dagger]) Professor, Department of Pediatrics, Kempegowda Institute of Medical Sciences, Bengaluru, Karnataka, India

** Junior Resident, Department of Pediatrics, M. R. M. C. Gulbarga, Karnataka, India

(Received 18 January 2011 and accepted 03 March 2011)

([PSI]) Correspondence at: #24, 7th main road Vasanthanagar, Bangalore 560052, Karnataka, India; Mobile: 09945690149; Email: kiranbylappa@gmail.com
Table 1a: Age distribution

Age (in yrs)   Frequency   Percent

2-5               19        19.0
6-10              18        18.0
11-15             28        28.0
>15               35        35.0

Total             100       100.0

Table 1b: Sex incidence

Sex            Frequency   Percent

Male               62        62.0
Female             38        38.0

Total             100       100.0

Female: Male Ratio = 1:1.6

Table 2: Distribution of risk factors

                      Allergic Rhinitis      Allergic Rhinitis with
                           (n=63)            bronchial asthma (n=37)

Risk Factor        Frequency   Percent (%)   Frequency   Percent (%)

Dust                  51          81.0          27          73.0
Weather change        43          68.3          35          94.6
Animal                 9          14.3           9          24.3
Food                  10          15.9          17          45.9
H/o Family atopy      25          39.6          24          64.8

Table 3: Distribution of signs and symptoms

                                               Allergic Rhinitis
                         Allergic Rhinitis      with bronchial
                              (n=63)             asthma (n=37)

Symptoms and symptoms   Frequency   Percent   Frequency   Percent

Rhinorrhoea                63        100.0       37        100.0
Nasal itching              24        38.1        16        43.2
Nasal obstruction          51        80.9        24        64.8
Pale mucosa                53         84         30        81.0
Sneezing                   32        50.8        12        32.4
Cough                      23        36.5        37        100.0
Wheezing                    1         1.6        37        100.0
Dyspnea                     0          0         12        32.4
Fever                       8        12.7         4        10.8

Table 4: Distribution according to mean

                  Diagnosis        n     Mean      SD      Minimum

Nasal         Allergic Rhinitis   63    20.10    22.230       0
Eosinophils
              Allergic Rhinitis   37    20.19    18.017       0
               with Bronchial
                   Asthma

                    Total         100   20.13    20.677       0

Blood         Allergic Rhinitis   63    506.60   351.066     95
Eosinophils
              Allergic Rhinitis   37    588.95   370.256     86
               with Bronchial
                   Asthma

                    Total         100   537.07   358.654     86

                                             't'     'p'
                  Diagnosis       Maximum   value   value

Nasal         Allergic Rhinitis     80      0.000   >0.983
Eosinophils
              Allergic Rhinitis     80
               with Bronchial
                   Asthma

                    Total           80

Blood         Allergic Rhinitis    1888     1.232   >0.270
Eosinophils
              Allergic Rhinitis    1650
               with Bronchial
                   Asthma

                    Total          1888

Table 5a: Distribution of nasal eosinophils according to the diagnosis

Nasal              Allergic     Allergic Rhinitis with
eosinophils        Rhinitis        bronchial asthma          Total

<10               30 (47.6%)          13 (35.1%)           43 (43.0%)

[greater than     33 (52.4%)          24 (64.9%)           57 (57.0%)
or equal to] 10

Total             63 (100.0%)         37 (100.0%)         100 (100.0%)

                  Chi-Square
                     Value          df   'p' value

                     1.482           1     .223

Table 5b: Distribution of blood eosinophils according to the diagnosis

Blood              Allergic     Allergic Rhinitis with
eosinophils        Rhinitis        Bronchial Asthma          Total

[less than or     29 (46.0%)          16 (43.2%)           45 (45.0%)
equal to] 440

>440              34 (54.0%)          21 (56.8%)           55 (55.0%)

Total             63 (100.0%)         37 (100.0%)         100 (100.0%)

                  Chi-Square
                     Value          df   'p' value

                     0.073           1     .0.787

Table 6a: Correlation between nasal and blood smear eosinophil counts
in allergic rhinitis and allergic rhinitis with bronchial asthma

                             Blood eosinophil

Nasal                         [less than or
eosinophil          >440      equal to] 440     Total

[greater than     41 (71.9)     16 (28.1)     57 (100)
or equal to] 10

<10               14 (32.6)     29 (67.4)     43 (100)

Total              55 (55)       45 (45)      100 (100)

                  Sensitivity   Specificity   PPV    NPV    Accuracy

Nasal
eosinophil           74.5          64.4       67.4   71.9      70

[greater than
or equal to] 10

<10

Total

Figures in parenthesis indicate percentage.

Table 6b: Correlation between nasal and blood smear eosinophil counts
in allergic rhinitis without bronchial asthma

                            Blood eosinophil

Nasal                         [less than or
eosinophil          >440      equal to] 440    Total

[greater than     25 (75.8)     8 (24.2)      33 (100)
or equal to] 10

<10                9 (30)        21 (70)      30 (100)

Total              34 (54)       29 (46)      63 (100)

                  Sensitivity   Specificity   PPV   NPV    Accuracy

Nasal
eosinophil           73.5          72.4       70    75.8      73

[greater than
or equal to] 10

<10

Total

Figures in parenthesis indicate percentage.

Table 7: Correlation of allergic rhinitis vs.
allergic rhinitis with asthma

                               Allergic
                Allergic     rhinitis with
              rhinitis (%)    asthma (%)

Sensitivity       73.5           85.7
Specificity       72.4            50
PPV                70            69.2
NPV               75.8           72.7
Accuracy           73            70.3
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