Arora: A study of various diagnostic tests to identify offending allergens in patients of allergic rhinitis in a tertiary care centre in northern India


Introduction

Asthma and allergies are common throughout the world, including India, with high burden on morbidity and cost implications. Allergic rhinitis being one of the commonest allergic disorders affecting nearly 26% of the population in India,1 extracts a considerable toll on patients life, cognitive and learning functions, decision making and self perception associated with low energy levels.2

Allergic rhinitis can develop at any age and it is often associated with asthma and sinusitis. Upto 80% of children with asthma develop symptoms before the age of five and allergic rhinitis often precedes asthma. There is also growing evidence that allergic rhinitis is a risk factor for asthma. Thus, today, allergic rhinitis is considered a global health issue with a considerable socio-economic impact, seriously affecting human productivity and qualify of life (QOL). In fact, the World Health Organization has also stepped up measures to increase the global awareness of allergic rhinitis and has introduced standard guidelines that would address effective treatment of rhinitis. Left untreated, allergic rhinitis can cause more serious conditions like asthma, sinusitis or ear infections. It is therefore important to decipher between allergies and colds.1

Air, without which the existence of life cannot be conceived, contains an array of biological particles including some like pollen, fungal spores and dust which may cause respiratory allergic disorders or precipitate their symptoms. In 1873, Sir Charles Harrison Blacklay for the first time reported that his own symptoms of seasonal allergic rhinitis were due to the pollen of grasses. He rubbed pollen into the skin of his arm and leg and elicited violent skin reactions, which probably was the first skin test with pollen. Subsequently aqueous extracts of pollen and other allergen.3

Allergy skin testing for immediate hypersensitivity is a cornerstone in the evaluation of patient with allergic disease and proper specific diagnosis is the foundation for successful management profile. Precise identification of allergens is worthwhile since it may lead to improvement in therapy. Skin Prick tests are done which are simple, quick and relatively cheap and have the advantage of providing the results while the patient is still in clinic.4, 5

The dominant inhalant allergens differ in different parts of the world. Therefore, in this study an attempt was made to find out the common inhalant allergens causing allergy in patients in and around Saharanpur.

Objective

The objective of study is to document common air borne allergens in and around Saharanpur as a cause of allergic rhinitis by SPT, Serum IgE levels, absolute eosinophil count and Nasal smear eosinophils.

Materials and Methods

Source of data

This is a prospective study which included patients presenting with signs and symptoms suggestive of allergic rhinitis like nasal itching, sneezing, nasal discharge or blockade attending the Out Patient Departments of Government Medical College Saharanpur and nearby hospitals during the period from July 2018 to June 2019.

Method of collection of data

A complete clinical examination was carried out and detailed history about chief complaints, aggravating factors, associated allergy and family history of allergy and other relevant details were taken and documented in the proforma.

Sample size

  1. Patients having symptoms of allergic rhinitis formed the study group.

Inclusion criteria

The clinically proven cases of allergic rhinitis i.e. the patients having symptoms of nasal itching, sneezing, discharge or blockade which occur for more than 1 hour on most days were included in study group.

Exclusion criteria

  1. Patients with other causes of rhinitis like Vasomotor rhinitis were excluded.

  2. Patients in whom complete work up was not possible were also excluded.

  3. Patients in whom skin prick test was negative were also excluded.

I. With strict aseptic precautions blood samples (about 5 ml) were collected by venepuncture and transferred in sample collection vials.

a) EDTA vial for complete blood count, differential leucocyte count and absolute eosinophil count which were obtained using automated hematology analyzer and results were validated manually at Department of Pathology, Government Medical College and Hospital, Saharanpur.

b) Plain vial for total serum IgE levels. This was possible in 33 patients. Total IgE levels were estimated using automated chemiluminescence analyser, Advia centaur, Bayer diagnostics, USA. The normal levels of total serum IgE levels age wise are:

<1 year: < 52.3 IU/ml

1-4 years: <351.6 IU/ml

  5-10 years: <393.0 IU /ml

11-15 years: <170.0 IU/ml

Adults: <150.0 IU/ml

II. Nasal smear for eosinophil count : Smears were made using nasal secretions, collected by asking the patient to blow out on the slide or by using cotton tipped nasal probe. Smears were air dried and stained by Giemsa stain. After staining, they were examined under oil immersion. Interpretation of nasal eosinophilia was done as per the following scale.

Table 1

Grading of nasal smear eosinophilia

-

< 5% Eosinophils

No Eosinophilia

+

10% Eosinophils      

Slight Eosinophilia

++

11-50% Eosinophils

Moderate Eosinophilia

+++

>50% Eosinophils

Marked Eosinophilia

III. Skin prick tests were performed using the allergens selected after study of common flora and fauna in and around Saharanpur city. Tests were done in Department of Pathology, Government Medical College, Saharanpur. The allergens were obtained from Creative diagnostic Medicare Private Limited Mumbai.

Credisol Prick Test solutions are glycerinated aqueous allergen extracts prepared after the method of Coca. These solutions are standardized in Protein Nitrogen Units (PNU) per ml. Prick test solutions were supplied in glass vials — type I containing approximately 1.5 ml of solutions sufficient for approximately 150 individuals tests. Vials were capped with polypropylene applicator which were coded according to the following chart.

Table 0

Pollen

Green

Fungi

Yellow

Dust mite

Orange

Insects

Red

Epithelial / Dander

Blue

Controls

White

Histamine was taken as the positive control and saline as negative control. The skin prick tests were performed on 50 patients as following.

Patients were asked to discontinue any medications that they were taking for allergic condition. Antihistamines and corticosteroids in high doses were asked to be discontinued 48 hours prior to testing. The test procedure consisted of cleaning the skin with isopropyl or 70% ethyl alcohol and allowing it to dry by evaporation. The areas chosen for doing the skin prick test were flexor surface of forearm and arm. The skin was marked with a ball point pen so as to identify and locate the site of each test. There was a difference of 2 cm in between the two test sites. A single drop of each test solution was placed. Skin prick test was performed using a sterile lancet. The lancet was placed through the drop of allergen extract at an acute angle to the skin and a shallow lift was made to elevate the small portion of epidermis without inducing bleeding. The lancet was raised for a second before skin was released. This was repeated for each drop of test solution. The lancet was carefully wiped on dry cotton wool in between the tests. Excess solution was removed by placing a tissue over the arm for moment.

The reactions were read after 15-20 minutes which appeared as raised wheal and erythema. Both wheal and erythema diameter were measured using a ruler supplied with the allergen kit and results expressed in mm. Grading of skin prick test was done by comparison to a histamine positive control.

Table 0

Grade

Percent of Area of Wheal / Erythema

Induced by Histamine

+

25

++

50

+++

100

++++

200

After recording the results, the skin was wiped with surgical spirit and the patient was given a tablet of antihistamine to prevent any local reaction that may occur at the site of test.

Results

The total number of patient studied in this series is 50. The age distribution of the patient ranged from 14 to 69 years. Majority of the patients belonged to second and third decades without sex predilection in our study. All patients subjected to SPT (46 allergens), nasal smear for eosinophil count and absolute eosinophil count in blood. Serum igE was done in 33 patients.

Absolute eosinophil count was raised in 56% of the patients, while it was normal in 44% of the cases.

Table 2

Absolute eosinophil count

No. of Patients

Percentage

Noremal (40 – 400)

22

44

Raised (>440)

28

56

Total

50

100

Raised counts ranged from 450-1161 cells/mm3 and normal counts ranged from 226 to 430 cells/mm3. Nasal smears for eosinophil was done in all included patient and result was tabulated in Table 5.

Table 3

Nasal smear for eosinophil count

Eosinophil Percentage in smear

No. of Patients

Percentage

< 5%

39

78

6-10%

04

8

11—50%

06

12

>50%

01

2

Total

50

100

Estimation of total serum IgE levels was possible in 33 patients. It was found to be raised in 32 patients (97%). All patients were subjected to SPT with 46 allergens. Thus, a total of 2300 SPTs were done and response was tabulated in Table 6. Maximum numbers of positive (2+, 3+, 4+) SPT was given by pollens in 40 patients (80%), followed by dust in 35 patients (70%). Mites and insects gave positive SPT in 26(52%) and 25 (50%) patients respectively, closely followed by fungi in 24 (48%) patients. Least reaction was given by epithelia in 20% of patients.

Table 4

Positive skin prick test response to various groups of allergens

Allergen Subgroups

No. of Patients

Percentage

Mite

26

52

Fungi

24

48

Pollens

40

80

Dust

35

70

Epithelia

10

20

Insects

25

50

Results of positive SPT with varied antigens were tabulated in table Table 7, Table 8, Table 9, Table 10, Table 11.

Table 5

Results of positive skin tests with various pollen antigens tested

Pollens

No. of Patients

Percentage

1. Cynodon dactylon

20

40

2. Parthenium hysterophorus

35

70

3. Sorghum vulgare

0

0

4. Pennisetum typhoides

6

12

5. Amaranthus spinosus

20

40

6. Argermone mexicana

20

40

7. Xanthium strumariuni

0

0

8. Brassica nigra

15

30

9. Ageratum conyzoides

0

0

10. Cocus nucifera

0

0

11. Peltophorum pterocarpum

0

0

12. Eucalyputs spp.

17

34

13. Ricinus communis

21

42

14. Cassia siamea

0

0

15. Zea mays

0

0

16. Acacia Arabica

0

0

17. Prosopis juliflora

16

32

18. Carica papaya

0

0

19. Ipomoea sp.

0

0

20. Helianthus annus

15

30

21. Cassia occidentalis

0

0

22. Azadirachta indica

0

0

23. Mangifera Indica

0

0

Table 6

Results of positive skin tests with four dusts tested

Dust

No. of Patients

Percentage

Cotton Dust

05

10

House dust

32

64

Hay dust

20

40

Grain dust (Rice)

06

12

Table 7

Results of skin prick test with three mite allergens tested

Mite

No. of Patients

Percentage

Mite (D-Farine)

25

50

Mite (D-Pteronyssinus)

9

18

Blomia sp.

6

12

Table 8

Results of positive skin prick test with antigenic extracts of various insects tested

Insects

No. of Patients

Percentage

Ants

0

0

Cockroach

14

28

Housefly

09

18

Mosquito

04

8

Table 9

Results of positive skin prick test given by different fungal antigens tested

Fungi

No. of Patients

Percentage

Aspergillus fumigatus

0

0

Aspergillus niger

15

30

Rhizopus nigricans

4

8

Penicillium Sp.

5

10

Candida albicans

0

0

Aspergillus versicolor

4

8

 

Table 10

Results of positive skin prick test with different epithelial antigens tested

Epithelia

No. of Patients

Percentage

Dog epithelia

5

10

Sheep’s wool

0

0

Human dander

0

0

Buffalo dander

7

14

Cat epithelia

3

6

Chicken feather

0

0

Discussion

The definitive diagnosis of nasal allergy requires identification of allergens and establishment of causal relationship between exposure to allergens and occurrence of relevant symptoms. Identification of allergens is possible by careful history taking and diagnostic procedure such as AEC, SPT, nasal eosinophil count and serum IgE level.

The purpose of the study was to determine and characterize common allergens using SPT in patients of allergic rhinitis in a tertiary centre and hospitals of Saharanpur, India

In the present study the majority of patients were in the second and third decades and very few patients in fifth and sixth decades, which is similar to studies done by Chaubey and Heda,6 Jha et al.7 and Gupta et al.8 Respiratory allergies commence early in the life and tend to become less frequent as age advances.

There is increase in incidence of allergy in younger age groups which may be due to more exposure of younger generations to environmental pollution which is increasing day by day.

Absolute eosinophil count was found to be raised in 56% of the patient where it ranged from 450 to 1161 cells/mm3 In patients who had normal counts (44%) absolute eosinophil count levels ranged from 226 to 430 cells/mm3. Singh and Chaymal9 found absolute eosinophil count to be raised in only 8 out of 30 patients (26.6%) and a level of not more than 600 cells/mm3 was noted. According to study done by Chaubey and Heda6 blood eosinophil counts ranged between 1 to 8% in 82% of the patients and in 6% of patients it was more than 10%. Thus absolute eosinophil count level is not raised in all the patients of allergic rhinitis as found in our study and other studies.

In the present study, nasal smear positivity for eosinophils was seen in 22% of cases while in remaining 78% of the cases it was either negative or less than 5%. Sood10 found nasal smear positivity in 80% of the patients, Chaubey and Heda6 found in 45% of cases, Wheldon et al.11 reported in 30% of patients and in the present study it was seen in 22% of the patients only. This may be due to, as pointed out by Wheldon et al.,11 because of difficulty in collection of specimens, timing of sample collection and other variables which influence the presence of eosinophils in the nasal smear.

In our study total serum IgE level measurements were possible in 33 patients. It was found to be raised in 32 patients (97% of cases). It has been argued that elevated IgE level have a high correlation with the pressure of inhalant allergy. King et al.12 noted that 99% of patients who had total IgE levels greater than 400 units/ml were positive for allergy as determined by RAST. Whereas only 33% of the patients who had total IgE level of less than 10 units/ml had significant allergy as determined by RAST. Although high levels of total IgE are predictive of significant allergy, low levels do not rule out clinically important allergic disease. Total IgE levels, therefore are not reliable indicators of absence of significant allergy. High positivity (97%) with respect to total IgE levels can be attributed to testing methodology used (Chemiluminscence Immunoassay) and rigid inclusion and exclusion criteria.

The most common allergens found in our study with the help of SPT were pollen (80%), dust (70%), mite(52%), insects(50%), fungi(48%) and epithelial antigen(20%) overall, pollen of Parthenium (70%) followed by house dust(64%) were found to be the most common offending allergens.

The most common allergen in our study was pollen (80%) and most common among all pollen was pollen of Parthenium, similar to study done by Chaubal and Gadve13 and it was found to be the second most common allergen after Amaranthus in Bangalore in a study conducted by Anand and Agashi.14 Next common offending pollen antigen noted was the pollen of Ricinus in 42% of the patients. This pollen was found to be the commonest offending allergen by Pherwani et al.15

Next common group of allergens after pollen antigens that gave positive reaction was dust in 70% of patients. Among the dust allergens maximum number of positive skin reaction were given by house dust in 32 patients, followed by hay dust in 20 patients, cotton and grain dust (rice) in 6 and 5 patients respectively. House dust was found to give maximum number of positive skin reactions which was similar to study done by Jha et al.7 It was found to be the second most common offending dust in a study done by Sethi S et al.,16 Pherwani et al.15 and Shanker et al.17 Raju et al.18 found grain dust as the most common offending dust, followed by cotton, hay and then house dust. This could be due to difference in climatic condition and the other environmental factors of the area where the study was conducted.

House dust mite (D.farine) gave positive reactions in 25 patients (50%) and D-Pteronyssius in 9 patients (18%) and Blomia species in 6 (12%) patients in the present study. House dust mite (D.farine) gave positive reaction in 50% of the patients while Singh and Chamyal9 reported in 43.3%, Raju et al.18 in 40% and Pherwani et al.15 in 31.3% of the patients.

In our study cockroach extract gave positive reaction in 28% of the patients, followed by housefly extracts in 18% of the patients and mosquito extracts in 8% of the patients. A maximum number of positive prick test response was given by Cockroach which is similar to study done by Pherwani et al15 and Chew FT et al.19 Raju et al,18 and Shanker et al17 reported maximum number of positive skin reactions in housefly followed by mosquito and cockroach extracts.

Six fungal extracts were used as allergens among which positive reaction was given by four fungal extracts, namely Aspergillus niger in 15 patients (30%), Aspergillus versicolor and Rhizopus nigricans in four patients each and Penicillum species in five patients. Prasad et al.20 In their study by SPT in Lucknow found marked positivity to Aspegillus spp., A.tenuis, F.solani. and R. Nigricans. Epithelial allergens as a group gave the least positive reaction in only 20% of the cases. Positive reaction was given by buffalo dander in 7 patients, dog epithelia in 5 patients and cat epithelia in 3 patients. No reaction was given by sheep wool, human dander and chicken feather extracts. Buffalo dander was the most common allergen identified which is in accordance with a study done by Gupta et al.21 is probably because most of the patients were from rural area.

The knowledge of common allergens found among study population in our region could assist medical practitioners in narrowing down the panel of allergens tested in daily practice leading to more specificity and cost-effectiveness.

Thus specific allergy test, including skin tests and specific lgE measurements are typically more useful compared to nasal smear eosinophils and AEC levels in the diagnosis and treatment of allergic rhinitis.

Source of Funding

None.

Conflict of Interest

None.

References

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Article History

Received : 15-03-2021

Accepted : 16-03-2021

Available online : 19-05-2021


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https://doi.org/10.18231/j.ijpo.2021.049


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