From ant bites and medicines to dust and pollen, allergies affect millions of Indians. While for many they are merely a tiresome nuisance, in some cases routine exposures can turn into life-threatening crises.

What began as routine health issues for three Chennai residents spiralled into prolonged medical ordeals, underscoring the unpredictable and sometimes life-threatening nature of allergies. Experts note that there is a need for better awareness about them to enable early diagnosis, as well as a need for more research in the Indian context into allergies and their triggers.

What patients experience

R. Neelakandan of Minjur underwent open-heart surgery in 2017. During his recovery, he developed persistent rashes after taking a prescribed medicine. His cardiologist referred him to a dermatologist, but even after two years of treatment, the condition showed little improvement. He was eventually advised to take monthly injections costing ₹19,000 each.

Relief came unexpectedly — through an autorickshaw driver.

“The driver took me to a doctor in Chennai who, he said, had treated him successfully,” Mr. Neelakandan recalls. “The doctor realised that I was allergic to a drug, and changed the medicine that I have to take regularly to another one. Earlier, I was spending nearly ₹25,000 a month on treatment and I felt I was a burden to my family. Now, my costs have come down to less than ₹2,000.”

For schoolteacher H. Deepalakshmi, what should have been a simple ant bite turned into a near-fatal emergency. Her blood pressure plummeted, she became dizzy and semi-conscious, and she had to be rushed to hospital. “After the first incident nine years ago, I started carrying the doctor’s prescription with me at all times,” says the 52-year-old. “Three years later, I was bitten again. I immediately showed the prescription at the hospital and received the injection. The symptoms were milder the second time and even less severe the third time.” Her doctor later explained that certain ant bites can trigger severe allergic reactions in susceptible individuals.

Rohini Karupiah, a college professor, has battled wheezing since childhood. During severe attacks she required oxygen support at home. Her bronchial allergy, she says, runs in the family. “My father and his sister both had wheezing, but my condition was much more severe,” she says.

While the triggers in these cases were very different, specialists say they reflect the broad spectrum of allergic disorders that affect millions of Indians.

More than a rash

‘Allergy’ is an umbrella term covering a range of immune-system responses. Symptoms can vary from mild skin rashes and itching to breathing difficulties and life-threatening anaphylactic shock. Allergic rhinitis — commonly triggered by dust, pollen and other airborne particles — is among the most widespread forms of allergy. Specialists, however, also encounter less common triggers, including insect bites, medications and substances that the body may have tolerated previously.

Chennai-based allergy specialist R. Sridharan says allergies can affect virtually every system in the body. “People can be allergic to mould, pollen, nuts, sunlight — even ant bites,” he explains. “Allergies may appear as skin rashes or hives, or manifest as allergic rhinitis. They can progress to sinus disease and, in some cases, bronchial asthma as well.”

According to Dr. Sridharan, allergic reactions are most often mediated by Immunoglobulin E (IgE) antibodies produced by white blood cells. Once the immune system identifies a substance as harmful, it may react aggressively whenever it encounters it. The reaction triggers the release of histamine, which dilates blood vessels and increases tissue permeability.

“The person feels hot, blood pressure can drop, and in severe cases the patient can go into shock,” he says. “Histamines cause swelling, warmth and itching. Treatment focuses on countering these effects.”

A growing concern

The scale of the problem is significant.

In their study, ‘Epidemiology of Allergic Rhinitis in India: A Systematic Review’, published in the International Journal of Academic Medicine and Pharmacy in 2023, researchers V. Sundararaman and A. Sathish Ponni estimated that nearly one in six people in Tamil Nadu may suffer from allergic rhinitis. The researchers noted that allergic rhinitis is a major public-health concern across India, although its prevalence varies widely across regions. Geography, climate, air quality and lifestyle factors all influence the incidence and severity of allergic disorders.

Allergies may be triggered by pollen, fungal spores and food items ranging from grains such as rice and wheat to legumes, chickpeas and vegetables. Increasing urbanisation, environmental pollution and changing lifestyles are also believed to be contributing to the rising burden of allergic disease.

Need for better research

Dr. Sridharan says eosinophil counts play an important role in identifying allergies. Common diagnostic tools include nasal smear and sputum eosinophil tests, ELISA tests to identify specific IgE antibodies and Phadiatop tests to detect inhalant allergies. Skin tests may also be used to pinpoint specific triggers. He cites research from the United States showing that some people who believed they were allergic to apples were actually reacting to birch pollen present on the fruit.

Despite the growing prevalence of allergic disorders, experts say India still relies heavily on treatment protocols adapted from Western populations.

In their paper, ‘An Appraisal of Allergic Disorders in India and an Urgent Call for Action’, published in the World Allergy Organization Journal in 2020, Mamidipudi Thirumala Krishna and colleagues argued that current management protocols are largely based on international guidelines developed using Western data. They noted a shortage of robust real-world studies assessing how well these approaches apply to Indian patients.

As the experiences of Neelakandan, Deepalakshmi and Rohini demonstrate, allergies are far more than seasonal irritants. Left undiagnosed or poorly managed, they can become chronic, debilitating and, at times, life-threatening conditions. For doctors and patients alike, identifying the trigger remains the first and most critical step. 

(R. Sujatha is an independent journalist based in Chennai. sujatha.raghunath@gmail.com)