|Year : 2016 | Volume
| Issue : 3 | Page : 99-104
Purview of allergens through skin test in Central India
Ashok Arbat, Sneha Tirpude, Mitesh K Dave, Sukhant Bagdia, Sameer Arbat
Department of Pulmonology, Ketki Research Institute of Medical Sciences Hospitals, Nagpur, Maharashtra, India
|Date of Submission||15-Jun-2016|
|Date of Acceptance||15-Aug-2016|
|Date of Web Publication||12-Oct-2016|
Department of Pulmonology, Ketki Research Institute of Medical Sciences Hospitals, 275 Central Bazaar Road, Ramdaspeth, Nagpur - 400 010, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction: Clinical history and examination are very important for determining allergy. The most common forms being bronchial asthma (BA) and allergic rhinitis (AR). A lot of patients respond to the primary line of treatment. Patients come forward with the objective of uprooting the cause of these allergies. Skin prick test (SPT) helps in finding the most likely cause after which we can offer them the desensitization and protective advice.
Objective: To evaluate the performance of various aeroallergens by assessment with SPT in Central India population.
Materials and Methods: One hundred and forty-three patients with BA and AR were subjected to SPT. SPT was performed with antigen extracts from India.
Results: Of the 143 patients, 86 (60%) patients had both BA and AR. These 143 patients showed 454 positive SPT results. Of the 454, 223 (49%) were positive for mites alone. Among the three mites tested for, Dermatophagoides pteronyssinus 81 (17.8%) was the most common. The study of seasonal distribution of allergens showed peaked results for mites in winter. Parthenium hysterophorus (congress grass) 11 (7.7%) was the most common pollen found.
Conclusions: The dust mite had the greatest frequency in this study. Humidity levels are critical for the growth of mites, which provides a valuable clue to protect against it. Avoiding the relevant allergens can be a remedy for AR patients and reduce the frequency of symptoms in asthmatics.
Keywords: Allergic rhinitis, bronchial asthma, dust mites, pollens, skin prick test
|How to cite this article:|
Arbat A, Tirpude S, Dave MK, Bagdia S, Arbat S. Purview of allergens through skin test in Central India. Environ Dis 2016;1:99-104
| Introduction|| |
Atopic march refers to the pattern of appearance of various symptoms of allergies. Individuals who do not follow this pattern are more likely to outgrow their allergies as the age progresses.  INSEARCH, GINA, and the WHO survey mention the worldwide prevalence of asthma to be between 2.05% and 3.5%.  In India, 20%-30% of the people have allergic rhinitis (AR), and 15% have bronchial asthma (BA).  It is imperative to identify and avoid the allergens. Skin prick test (SPT) is one such useful tool. The results can be interpreted in a short span.  The sensitivity and specificity of SPT are 70%-95% and 80%-97%, respectively, for inhalant allergies.  A correlation of the results with history stands important. Often there is no help from history in a setting like ours. Patients are illiterate and negligent about the symptoms; they stop medicines in between as they are unable to bear the long-term cost of treatment. If we study the pattern of allergens and resort to preventive measures, patients will benefit with the low requirement of medicines. Studies pertaining to characteristics and pattern of allergens in Central India are lacking. The epidemiology of allergens differs from region to region. Awareness of allergy and identification of the most prevalent aeroallergens are important keys to preventive measure.
| Materials and Methods|| |
The positive SPT patients during the last 1 year were studied in the Department of Pulmonology at the Ketki Research Institute of Medical Sciences, Nagpur.
Patients withhold antihistamines 5 days prior to the test. The allergens are histamine-positive and buffered saline negative controls purchased from Creative Drug Industries (Mumbai, India). In each patient, 71 skin prick are done using 30 type of pollen allergen, 14 types of fungus, 3 types of mites, 9 types of dust allergens, 5 types of epithelial allergen, and 10 types of insects. During the test, a small drop of test reagent is dropped on the volar aspect of the forearm. Normal saline (negative control) and histamine (positive control) are also dropped at the same time. The lancet tip is passed through the drop about 1 mm deep. The drop is gently wiped off. The test reading is done after 15-20 min. Atopy is defined as a positive SPT in which the wheal diameter is >3 mm as compared to the negative control for at least one aeroallergen. This test can be performed in all age groups including babies. In Department of Pulmonology, we mainly get a nonpediatric population. The data were tabulated in an Excel sheet and studied.
| Results|| |
SPT produced a positive result in 143 out of total 620 asthmatics and AR. Patients with SPT positivity to single allergen were 68 (47.6%), while 75 (52.4%) had skin test positivity to multiple allergens. The total number of positive tests was 454.
[Figure 1] shows the skin test positive patients categorized according to their age. One hundred and thirty (91%) belonged to 10-49 years of age. Thirteen (9.1%) were in 50-69 years of age group and 1 patient was <10 years of age.
Eighty-six (60%) patients had both BA and AR. While 43 (30%) had AR and 14 (9.8%) had BA alone [Figure 2]. In terms of gender, 60 (42%) were females and 83 (58.4%) were males [Figure 3].
The SPTs showed 454 positive results with following allergens. Mite 223 (49%) was the most common allergen found [Figure 4], followed by pollen 99 (21.8%), dust 70 (15.4%), insect 48 (10.6%), fungus 14 (3%), and animal epithelia (0).
Different types of dust mites were tested with. Dermatophagoides pteronyssinus 81 (56.6%) was the most common causing symptoms. Dermatophagoides farinae 70 (49%) and Blomia species 72 (50.4%) were the other two types of mites [Figure 5].
Among dusts 70 (15.4%), grain dust rice 29 (20.28%), and wheat dust 15 (10.5%), cotton dust 7 (5%), spider web dust 6 (4.2%), house dust 5 (3.5%), hay dust 4 (2.8%), and saw dust 3 (2%) were noted.
Thirty different pollens were tested for pollens 99 (21.8%), commonly responsible were Parthenium hysterophorus (congress grass) 11 (7.7%), Cynodon dactylon (Bermuda grass) 8, Ipomoea species (Morning glory) 9, Holoptelea integrifolia (Indian Elm tree) 9, Cassia sp. (golden shower tree) 6 (1.4%), and Ischaemum sp. (crabgrass) 6 (1.4%). Following [Figure 6] shows the positive pollens in order of frequency. [Table 1] shows less common pollens.
Insect panel testing showed grasshopper 17 (3.4%) to be the most frequent. Followed by rice weevil 9 (1.8%), ant 7 (1.8%), mosquito 7 (1.8%), cockroach 3 (0.6%), honey bee 2 (1.39%), housefly 2 (0.4%), wasp 1, and cricket 1 [Figure 7].
Fungus Alternaria alternans 5 (3.29%) was most common. Other fungii were Phoma tropicalis 2, Aspergillus niger 1, Aspergillus flavus 1, Aspergillus tamari 1, Cladosporium herbarum 1, Helminthosporium sp. 1, Penicillium sp. 1, and Tricoderma viride 1 [Figure 8].
On studying the number of patients month wise, there were 28 (19.6%) patients in the summer season which is between March and May, 34 (23.8%) patients from June to August, and 62 (43.3%) from September to December. These 62 had 119 positive tests. This surge in a number of patients during winter was due to increased mite test results 115 (96.6%) [Figure 9] and [Figure 10].
[Figure 11] shows the distribution of patients. Those belonging to Nagpur are 32 (22.8%), adjacent districts of Maharashtra 28 (19.6%) such as Akola, Amravati, Bhandara, Wardha, Gadchiroli, and Umred. Moreover, neighboring states such as Madhya Pradesh 76 (53.1%), Chhattisgarh 4 (2.8%), Telangana 2 (1.3%), and Rajasthan 1 (0.7%).
| Discussion|| |
A study by Prasad et al. showed a very high 60%-80% comorbid rate of asthma and rhinitis. In our study also, majority 86 (60%) had both Asthma and Rhinitis. Forty-three (30%) had AR and 14 (9.8%) had BA alone.
One hundred and thirty (91%) belonged to 10-49 years of age. In the Department of Pulmonology, here we majorly get nonpediatric patients. Thirteen (9.1%) were in 50-69 years of age group and one patient was <10 years of age.
A positive SPT indicates sensitivity to the allergen, while an allergy is a hypersensitivity. Neither SPTs nor blood tests alone can reveal if a person has an allergy. Our patients who were diagnosed to have BA and AR were the ones subjected to SPT. This is done to reduce the false positives. Thus, only after a clinical correlation with the SPT we can surely estimate the real allergens.
SPTs were positive to mite 223 (49%) followed by pollen 99 (21.8%), dust 70 (15.4%), insects 48 (10.6%), and fungus 14 (3%). None had animal epithelia allergy. Aeroallergens differ from one place to the other; however, in Asia, the order is house dust mites, pollens, insects, molds, and fungi. 
D. pteronyssinus 81 (17.8%) was the most common mite leading to symptoms in patients. Dermatophagoides farinae 70 (15.4%) and Blomia species 72 (15.8%) were the other two types of mites.
Higher levels of mites are noted in damp homes indicating that humidity plays a role in their survival.  Maunse et al. in (1968) reported the absence of mites from rooms with an average relative humidity below 60%.  In Central India, the temperature is high and conditions are dry, especially during the 4 months of summer (February-June) which restrict the growth of mite population. The population starts growing again during the rainy season. In our study too, there was a rise noted. 119 SPTs were positive during monsoons. Out of which 115 (43.4%) were positive for mites alone. As compared to summers which saw only 31 patients to have symptoms and 25 (24%) SPTs positive for mites. While the other group of allergens, for example, pollens showed near similar frequency in all the months. Thirteen (26%) in summers and 16 (29%) in winters and 16 (13%) in monsoon. In a survey of homes with dust mites, 60% of the dust mite population is reported from the bed, mattresses, and pillows, 30% in upholstery, and 10% in the carpet. Indoor lifestyle results in increase indoor humidity and exposure to allergens. 
Among dusts 70 (15.4%), grain dust rice 29 (6.4%), wheat 15 (3.3%), cotton dust 7 (1.5%), spider web dust 6 (1.3%), house dust 5 (1%), and saw dust 3 (0.6%) account for the majority of dusts. In a similar study of Northern India, most common dusts were house dust (25%), followed by wheat dust (12.5%), cotton dust (6.3%), and paper dust (4.2%).
Our study showed positive tests to thirty different pollens 104 (21%). P. hysterophorus (Congress grass) (11), C. dactylon (Bermuda grass) (8), Ipomoea species (Morning glory) (9), Holoptelea integrifolia (Indian Elm tree) (9), Cassia (golden shower tree) (6), and Ischaemum (crabgrass) (6) were the common ones. Parthenium (congress grass) was also found to be in the common pollen allergens list of studies conducted by agriculture departments of India.  There are several pollens produced by a single plant as much as several million. Furthermore, its allergy is variable in various ecozones. Hence, it is imperative to identify the pollens, of every region and prepare extracts from them for testing.
Alternaria alternans 5/14 (3.1%) was the most common type of fungi in our study. Agashe  found mold spores of Cladosporium, Periconium, Nigrospora, Alternaria, Helminthosporium, Smut spores, Aspergillus, and Penicillium to be the common aeroallergens. Alternaria alternans is found in cosmopolitan and is Isolated from a variety of plants and from the soil. Individuals having frequent respiratory problems during activities like gardening may point toward a mold allergy.
Patients coming to Ketki Research Institute of Medical Sciences reside within a diameter of approximately 1000 km. Patients are from Nagpur (23%), as well as adjacent districts (25%) such as Akola, Amravati, Bhandara, Wardha, Gadchiroli, and Gondia. Majority of them are coming from Madhya Pradesh (46%). While Chhattisgarh (4%), Telangana (1%), and Uttar Pradesh (1%) also account for some patients. This implies a Central India population.
As the number of infections decreases, the chances of autoimmunity and allergic disease increase. This is due to redirection of the immune response toward a Th2 phenotype as per the hygiene hypothesis.  Moreover, exposure to inorganic and organic dusts, air pollutants, seasonal viral infections (isolated or in various combinations) enhances airway responsiveness to aeroallergens in atopic subjects. The prevalence of allergic diseases in Asia is 29.1% (asthma) up to 45% (AR) mostly in low- and middle-income countries.  In addition, awareness of the condition remains generally low.
| Conclusions|| |
This is the first study in Central India region for determining the various susceptible aeroallergens. Based on this, AR and asthmatics should be offered an effective education about the disease, avoidance of relevant allergens, and importance of compliance with treatment. SPT should be considered to be the test of choice in clinical practice after correlating it well with history. Sometimes when patients are unable to give specific history, we must test the most common locally prevalent allergens too for which this study is helpful. The dust mites are present all year round, but during the summers in Central India, their number goes down due to low humidity. We have tried to highlight the common allergens in Central India subpopulation, their seasonal variation, and the need to study them further with respect to cross-reactivity among various aeroallergens, the response to treatment, and the need for more sensitive extracts.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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