A vastly complicated disease, allergic disorders, such as anaphylaxis, allergic rhinitis, eczema and asthma, now afflict roughly over 30% of people in India the developed world. Here are some specifics to help you understand allergies better.
If you’ve broken out into hives after eating shell-fish on your Goa vacation or experienced a sudden asthma attack on the street after inhaling a toxic substance or been flattened out after a bout of incessant sneezing because you inhaled passive smoke at your house party – you probably will understand what it is to experience allergies.
What is an allergy?
An Allergy is a condition of overreaction of the immune system in certain individuals to some harmless substances. The substance that causes allergic reaction is called an allergen. These reactions are acquired, predictable, and at times rapid.
Why do some people have it and not others?
It is quite common for allergy sufferers to react more to seasonal changes, (like currently); but why do some people seem prone to allergies more than others.
Yes you guessed right. The tendency to develop allergies is often hereditary. But just because you, your partner, or one of your children might have allergies doesn’t mean that the whole family will be allergic. And someone usually doesn’t inherit a particular allergy, just the likelihood of having allergies.
Some family members have allergies even if no family member is allergic, and those who are allergic to one thing are likely to be allergic to others.
What Cause Allergies?
Risk factors for allergy:
1) Host
2) Environmental
Host factors include heredity, sex, race, and age, with heredity being the most significant.
However, there have been recent increases in the incidence of allergic disorders that cannot be explained by genetic factors alone. Infectious diseases during early childhood, environmental pollution, allergen levels, and dietary changes are the four main reasons for allergies.
Common Airborne Allergens
Some of the most common things people are allergic to are airborne (carried through the air):
Dust mites are microscopic insects that live all around us and feed on the millions of dead skin cells that fall off our bodies every day. They’re the main allergic component of house dust. Dust mites are present year-round and live in bedding, upholstery, and carpets.
Pollen is a major cause of allergies. Trees, weeds, and grasses release these tiny particles into the air to fertilize other plants. Pollen allergies are seasonal, and the type of pollen someone is allergic to determines when symptoms happen.
Pollen counts measure how much pollen is in the air and can help people with allergies predict how bad their symptoms might be on any given day. Pollen counts are usually higher in the morning and on warm, dry, breezy days, and lowest when it’s chilly and wet.
Molds are fungi that thrive both indoors and outside in warm, moist environments. Outdoors, molds can be found in poor drainage areas, such as in piles of rotting leaves or compost piles. Indoors, molds thrive in dark, poorly ventilated places such as bathrooms and damp basements. Molds tend to be seasonal, but some can grow year-round, especially those indoors in humid conditions.
Pet allergens are caused by pet dander (tiny flakes of shed skin) and animal saliva. When pets lick themselves, the saliva gets on their fur or feathers. As the saliva dries, protein particles become airborne and work their way into fabrics in the home. Pet urine also can cause allergies in the same way when it gets on airborne fur or skin, or when a pet pees in a spot that isn’t cleaned.
Cockroaches are also a major household allergen, especially in inner cities. Exposure to cockroach-infested buildings may be a major cause of the high rates of asthma.
Toxic fumes, smoke and chemicals can vary from a seemingly innocuous detergent to harmful variants of mosquito repellants, bleaching products etc. Environmentally, we know too well the potential risks and damage of vehicular and industrial carbon emissions.
Common Food Allergens
Milk and milk proteins. Mostly cow’s milk and cow’s milk-based formulas are a major source of allergies. If you are lactose intolerant you probably identify implicitly with this allergy.
Fish and shellfish. These allergies are some of the more common adult food allergies and ones that people usually don’t outgrow. Fish and shellfish are from different families of food, so having an allergy to one does not necessarily mean someone will be allergic to the other.
Peanuts. Peanut allergies are on the rise, and as are allergies to tree nuts, such as almonds, walnuts, pecans, hazelnuts, and cashews. Most people do not outgrow peanut or tree nut allergies.
Soy. Soy proteins are often a hidden ingredient in prepared foods.
Wheat. Wheat proteins are found in many foods, and some are more obvious than others. Although wheat allergy is often confused with celiac disease, there is a difference. Celiac disease is a sensitivity to gluten (found in wheat, rye, and barley). But a wheat allergy can do more than make a person feel ill — like other food allergies, it also can cause a life-threatening reaction.
Allergy and Inflammation
While some people are sensitive to one particular allergen, others may be allergic to many substances.
Allergic reactions are excessive activation of certain white blood cells called mast cells and basophils by a type of antibody called immunoglobulin E (IgE). This results in an inflammatory response which can range from uncomfortable symptoms to life threatening situations.
About one third of the population suffer from one or other form of allergy. Children are more affected by allergies which may or may not subside in adulthood.
In allergy sufferers persistent or repetitive exposure to allergens, which typically are intrinsically innocuous substances common in the environment, result in chronic allergic inflammation. This in turn produces long-term (inflammatory) changes in the structure of the affected organs and substantial abnormalities in their function.
Types of allergies
Asthma and rhinitis are the common respiratory allergies. Eczema, urticaria (hives) and atopic dermatitis are some of the common skin allergies.
What to expect during an allergy attack
Based on the part affected, the allergies vary.
You may have skin allergy (Rashes on the skin as in the image above), eye allergy or respiratory allergies.
Biomass fuel such as cow dung and coal used in chullah, especially in poorly ventilated kitchens increases risk of asthma, rhinitis and upper respiratory tract infections. Such people are likely to suffer from Chronic Obstructive Pulmonary Diseases (COPD).
Latex is source of allergy, which trigger skin, respiratory and systemic reactions. The most problem is irritation or inflammation of skin leading to a condition called contact dermatitis. Sweating or rubbing the area under the glove aggravates the lesions, possibly leading to ulcerations. Those who are sensitive to latex may also be allergic to banana.
The severity and appearance of the symptom depend on immunity, type and amount of exposure to the allergen.
Irritation of nose, blocked or running nose and sneezing are common nasal symptoms.
Itching or irritation with watering and or redness of eyes is a common eye symptom.
In severe cases, there may be tightness of chest, often leading to breathing difficulty, mucus secretion, coughing and wheezing.
Changes in the season, weather and place may trigger an allergic reaction.
Food allergy is the inability of certain individuals to break down some foods which are otherwise harmless to others.
In my opinion we need to do a separate article on just food allergies as lately the innumerable dietary preferences point to an increasing hyper sensitivity to many foods.
Food allergies may cause tingling mouth, rashes in the body, swelling of the lips, tongue, face or throat and even severe reaction called anaphylaxis, depending on the allergen. Diarrhoea, stomach pain, urticarial rashes or at times vomiting are found in mild allergies.
Sometimes indigestion due to a disagreeable food is considered as allergy but is now being identified as an allergic inflammation.
For example, a rotten egg may cause diarrhoea or vomiting due to indigestion, but to those who are allergic to egg they can react physically after eating a small piece of cake with egg.
The severity and onset of the symptom will depend on the host immunity, type and quantity of exposure of the allergen.
In drug sensitivity, the host is sensitive and the reaction may be severe, sudden and even life threatening. This may cause hives, itchy skin, and rashes on the body, swelling of the face and wheezing. The body gets swollen, patient may get breathlessness and at times lead to respiratory distress.
This is called anaphylaxis.
Anaphylaxis symptoms usually occur within minutes of exposure to an allergen or at times may be delayed. During anaphylaxis skin reactions may occur with hives flushed or pale skin, a feeling of warmth, sensation of a lump in the throat, constriction of the airways and a swollen tongue or throat, which can cause wheezing and breathing trouble. At times there may be acute problems like weak or rapid pulse, nausea, vomiting, diarrhoea, dizziness or even fainting. This is a serious emergency which requires immediate medical attention.
Insect sting may cause swelling of the site, itching or hives all over your body with symptoms such as cough, chest tightness, wheezing or shortness of breath and at times anaphylaxis.
The psychological fallout of being allergic
Most allergies interfere with sleep, intellectual functioning and recreational activities. Food allergies may often lead to anxiety and fear of eating food from unknown places.
Allergies are chronic conditions and most often requisite a change in lifestyle or even profession to avoid hazardous allergens.
So how do you know if you have an allergy or just a one-time extreme reaction?
Normally allergies are diagnosed based on the history of symptoms after numerous exposures to an allergen. Specific diagnosis is done through measurement of Immunoglobulin’s. Immunoglobins are the antibodies produced by the white blood cells of our body.
What are the treatments available?
Allergy is a disease, which if detected early, can be treated successfully to a great extent.
The best option is to avoid the allergens that trigger the allergic reaction. At times even small quantity of an allergen could produce severe allergic response in sensitive individuals. As the individual response to an allergen is the important factor for the flare up of symptoms, more attention is needed on the sensitivity of the individual rather than the substance that cause the allergy.
Symptoms of allergy can be controlled through antihistamines and corticosteroids. Both these medicines have their own limitations, side effects and benefits.
Immunotherapy or Allergy Shots is another approach used to desensitise the people with specific allergen. This is a long continued process that could gradually desensitise people who are sensitive. It involves giving gradually increasing doses/ shots of the substance, or allergen, to which the person is allergic. The incremental increase in the allergen causes the immune system to become less sensitive to the substance, probably by causing production of a “blocking” antibody, which reduces the symptoms of allergy when the substances is encountered in the future. Immunotherapy also reduces the inflammation in cases of rhinitis and asthma.
Before starting treatment, it is imperative that the physician and patient identify trigger factors for allergy symptoms.
Immunotherapy is usually recommended only if the person seems to be selectively sensitive to several allergens.
A Short Note on Allergy Tests :
Allergy tests may help you find allergies to things you eat, touch, or inhale. They are usually skin or blood tests.
However, allergy tests alone are generally not enough. It is important to have a doctor’s exam and medical history first to help diagnose allergies. If the exam and medical history point to allergies, allergy tests may help find what you are allergic to. But if you don’t have symptoms and you haven’t had a medical exam that points to an allergy, you should think twice about allergy testing.
Unreliable test results can lead to unnecessary changes in your lifestyle. This happened to me.
If the test says you are allergic to some foods, such as wheat, soy, eggs, or milk, you may stop eating those foods. You may end up with a poor diet, unnecessary worries and frustration, or extra food costs. If the test says you are allergic to cats or dogs, you may give up a loved pet.
And tests for chronic hives—red, itchy, raised areas of the skin that last for more than six weeks—can show something that may not look normal but is not a problem. However, this can lead to anxiety, more tests, and referrals to specialists.
So, when should you have an allergy test?
If you have allergy symptoms, you may get relief from self-help steps and over-the-counter drugs. If these steps do not help your symptoms, then it is time to see your doctor.
Your doctor should ask you about your medical history and make sure you get the right tests. If your medical history suggests that you have an allergy, your doctor might refer you to an allergist or immunologist (doctors who specialise in allergies) for testing.
- A skin test is the most common kind of allergy test. Your skin is pricked with a needle that has a tiny amount of something you might be allergic to.
- If you have a rash or take a medicine that could affect the results of a skin test, you may need a blood test.
- For chronic hives, you usually do not need an allergy test. However, your doctor might order tests to make sure that the hives are not caused by other conditions, such as a thyroid disorder.
What next for allergy sufferers?
Please note I use the word “sufferer” as I have personally experienced a lifetime of allergies, in myself and in my family. Like most things one doesn’t realise how draining and exhausting an allergy attack can be until you experience it for yourself.
That the world of allergies is complicated is a gross understatement.
The problem with the field of allergies, is that it is still in its infancy, even in the West. Allergy research is hampered by the fact that one cannot easily determine whether a person is suffering from allergy or an extreme reaction to local pollution. For example a visitor from Bengaluru to Mumbai can experience severe humidity-related skin allergies whereas a Mumbaikar could get an extreme allergy to pollen while visiting Bengaluru.
The recent progress in our understanding of the genetic, environmental, tissue-specific and immunological factors that contribute to the development of allergic disorders and allergic inflammation has suggested possible new approaches for managing, treating or even preventing these disorders.
Will more specific or potent targeting afford a substantial improvement over current approaches? Will marshalling the current knowledge of the immunobiology of allergy and tolerance allow researchers to devise ways to prevent allergic sensitisation (for example, by improving epithelial / skin barrier function in individuals in whom it is impaired) or to induce tolerance by safer and more effective forms of allergen-specific immunotherapy?
Another challenge is that allergy sufferers are not quite sure who to go to and visit anyone from dermatologists to surgeons. Perhaps we have a paucity of allergy specialists in India and this facet of healthcare needs to be addressed.
Time will tell. Such efforts are important because, although most patients with allergic disorders can be helped by current management strategies, these complex ‘disorders of advanced civilisation’ have so far been difficult to control in many patients, let alone to prevent or cure.
