Introduction
Allergic rhinitis being one of the commonest Allergic disorders affects 26% of the population in India.1 The prevalence of allergic rhinitis is increasing in India, possibly due to change in environment.2 More than 20% of world population suffers from IgE associated Allergic disorders such as asthma, acute urticaria and food allergies. 3 Skin prick test (SPT) is the most effective and cheapest diagnostic method to detect IgE mediated Allergic reactions. 4 Positive SPT with a history suggestive of clinical sensitivity to identifiable allergens strongly incriminates the allergen as a contributor to Allergic rhinitis.
The type of aeroallergens differ variedly depending on the geographic region and climatic conditions, and in India specially, due to its huge size and varied climatic condition. India, being a populous country with diverse food habits due to socio cultural and communal differences, also afforded us an opportunity to study the sensitivity to common food allergens in patients of our region. The present study was carried out to identify the patterns of SPT to various types of allergens for avoidance therapy and immunotherapy in patients attending an pulmonary medicine and ENT clinical in tertiary centre and hospitals in Saharanpur.
Materials and Methods
Subjects
This is a prospective observational study on 50 consecutive patients of allergic rhinitis in an pulmonary and ENT OPDs between July 2018 and June 2019.
After taking clinical history and physical examination of patients in pulmonary medicine and ENT outpatient departments, diagnosis of allergic rhinitis was made on the basis of the Allergic Rhinitis and its impact on Asthma guidelines(2016 revised).5
Inclusion criteria
Consecutive patients of allergic rhinitis attending the pulmonary medicine and ENT outdoor department, between 10 to 65 years of age group and ready to give informed consent for inclusion in the study and SPT were enrolled.
Clearance and approvals
Clearance was obtained from the institutional ethic committee. Informed consent in their vernacular language was obtained from the patients.
Skin prick test procedure
The selected patients for SPT were discontinued on medication that interfere with test results, decrease systemic allergic reactions. The allergens were obtained from Creative diagnostic Medicare Private Limited Mumbai The Allergens included 23 Pollens, 4 inscets, 3 mites, 4 types of common dusts,6 fungi and 6 animal epithelia and histamine and saline as controls. The test procedure consisted of cleaning the skin over flexor aspect of forearm and arm with isopropyl alcohol and allowing it to dry. The skin was marked with a ball point pen to identify and locate the site of each test with a difference of 2cm in between the two test sites. A single drop of each test solution was placed. SPT was performed using a sterile lancet. The lancet was placed through the drop of allergens 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 a dry cotton wool between the tests. Excess solution was removed by placing a tissue over the arm for a moment
The reactions were read after 15 to 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 the results expressed in mm. Grading of skin prick test was done by comparison to a histamine positive control and a reaction of >3mm than that produced by the negative control on SPT was considered as positive reaction.
The statistical analysis was done using SPSS version 15.0 statistical Analysis Software.
Results
The age distribution of the patient ranged from 14 to 69 years. Majority of patients belonged to second and third decades without sex predilection in our study. Table 1
A total of 50 patients fulfilling the inclusion criteria were selected and subjected to SPT with 46 allergens in each patient. Thus, a total of 2300 SPTs were done and response was tabulated. Table 2
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. Results of positive SPT with varied antigen were tabulated. Table 3, Table 4, Table 5, Table 6, Table 7 .
Table 1
Age distribution of patients
|
Age (Years) |
No. of Patients |
Percentage |
|
0—9 |
0 |
0 |
|
10—19 |
8 |
16 |
|
20—29 |
14 |
28 |
|
30—39 |
11 |
22 |
|
40—49 |
10 |
20 |
|
50—59 |
05 |
10 |
|
60—69 |
02 |
04 |
|
Total |
50 |
100 |
Table 2
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 |
Table 3
Results of positive skin tests with various pollen antigens tested
Table 4
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 5
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 6
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 |
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 SPT. SPT is highly sensitive, specific, simple, inexpensive and reproducible investigation for diagnosis of allergic diseases.6
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.
The most common allergens found in our study 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 gadve7 and it was found to be the second most common allergen after Amaranthus in Bangalore in a study conducted by Anand and Agashi.8 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. 9
Cynodon, Amaranthus and Argemone gave positive reactions in 40% of the patients each. Prosopis juliflora gave positive reactions in 32% of the patients in the present study which is also similar to the study done by Raju et al 10 who found it is 30% and Gupta M.C. et al11 who found it is 32.46%.
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.12 It was found to be the second most common offending dust in a study done by Sethi S et al,13 Pherwani et al 10 and Shanker et at 14. Raju et al 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 Chamyal 14 reported in 43.3%, Raju et al in 40% and Pherwani et al in 31.3% of the patients. It was commoner than the D.Pteronyssimus as also shown by Kashef S. et al. 15
Estimates suggest that insect comprise 80% of the world’s species. 16 Dissemination of insects by aircurrents is significant in accounting for seasonal flare-ups of nasobronchial allergy.17 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 at and Chew FT et al.18 Raju et al, and Shanker et al 19 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.
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