Allergic Disorders - Our Experience

Allergic disorders, which encompass diseases such as asthma, rhinitis, urticaria (hives), food allergy, drug allergy and others, are a common health concern in India. Among these, asthma and allergic rhinitis contribute to the majority of allergy-related illnesses affecting Indians. While epidemiological data on the prevalence of asthma and rhinitis in India is available, the actual burden of other allergic disorders in the community remains unknown. In the past, the incidence and prevalence of allergic disorders were low in India when compared to Western countries; however, India has seen a sharp rise in recent years.

An estimated 300 million people worldwide suffer from asthma, of which 37.9 million reside in India. The burden of asthma in India exceeds the number of people with HIV infection or tuberculosis. Phase III of the International Study of Asthma and Allergy in Children (ISAAC) reported an overall wheezing prevalence of 7% among Indian children aged 6-7 and 13-14 years, with certain regions showing rates as high as 10-20%. More than half of the asthmatics in India are poorly controlled, and this continues to be a major cause for emergency room visits, hospitalizations, and deaths. A study in India reported that the prevalence of allergic rhinitis was 11.3% among children aged 6-7 years and 24.4% among children aged 13-14 years. Studies have shown that the overall prevalence of allergic rhinitis in India varies between 20-30%. The prevalence of food allergy ranges between 0.5-1%.

The burden of allergic disorders differs across India. This may be due to varying weather conditions, air pollution levels, heterogeneity in aerobiology, diet and cultural and religious factors. Air pollution is a major risk factor in the pathogenesis of allergic diseases like asthma and rhinitis. Globally, India ranks among the highest in the concentration of air pollution caused by biomass, fossil fuels and vehicular exhaust. About 77% of the Indian population is exposed to PM 2.5, which exceeds the permissible limit of 40 μg/m³ set by India’s National Air Quality Standards. India is the third largest producer of green house gases worldwide (3619.8) million tonnes in 2018) after USA and China. Levels of PM 2.5 in Indian metropolitan cities such as New Delhi, Kolkata, Mumbai and Bangalore are among the highest in the world. Global warming causes early pollination, prolonging the hay fever season, enhancing the pollen load and altering allergenicity. Epidemiological studies suggest that higher air pollution levels are associated with a higher prevalence of asthma, particularly among children, an increase in the severity of asthma, and also an escalation in its exacerbations leading to hospitalizations and deaths. We have also experienced a rapid rise in food allergy and atopic eczema in the last 1-2 decades, which are predominantly attributed to factors such as changing lifestyles, dietary patterns, urbanization, and globalization.

The management of allergic disorders includes pharma-cotherapy, immunotherapy and educating patients and the community on the various preventive measures for these disorders. Many allergy-related diseases can be prevented by adopting a proper diet and a healthy lifestyle. Some studies have demonstrated that an Indian rural lifestyle, exclusive breastfeeding and a traditional Indian diet are protective against allergic disorders. Early diagnosis and prompt treatment of allergic disorders have been shown to enhance the quality of life of afflicted individuals. Immunotherapy, also known as desensitization, is the only treatment modality that alters the natural history of the disease and aims to provide a permanent cure. The management of allergic disorders in India remains suboptimal due to a lack of trained physicians in the field of allergy, paucity of diagnostic facilities, and an associated high cost of formal diagnosis and treatment.

From a research perspective, India presents an invaluable opportunity to learn about changing trends, risk factors and new disease phenotypes and improve our current understanding of the aetiology of allergic disorders. The need of the hour is a multidisciplinary, cohesive approach involving healthcare professionals, policymakers, national scientific societies and local governments, all working to effectively prevent and control allergic diseases.

In my experience with allergies in Bangalore for over a decade, allergy cases have nearly doubled. This rise may be attributed to increasing air pollution from vehicles, poor road conditions, lifestyle and dietary habit changes. Notably, some individuals experience allergy symptoms only while in Bangalore. This can be explained by factors like air pollution and pollen, which are characteristic of this climate. The patients visiting hospitals represent only the tip of the iceberg, as most allergy cases remain underdiagnosed and undertreated. There is a pressing need for more trained allergy specialists and stronger government action to combat air pollution.