Written by Shraddha Rupavate |Updated : June 29, 2015 10:05 AM IST
If you notice sudden swelling, itchiness or reddening of different parts of the body such as lips, face, tongue and throat or if you suffer from stomach ache, nausea and breathing difficulties after eating foods such as groundnuts, milk, eggs or wheat, you probably are suffering from food allergy. But, you are not alone - around 6% of children and 4% of adults suffer from this problem all over the world.
You could be suffering from these allergies since childhood or could have developed these as an adult. It is also possible that some allergies that you develop in childhood (such as milk allergy) may disappear later in life while a few (such as peanut and wheat allergy) may last forever.
If you have been ignoring the above symptoms and not doing much about it, you really ought to take food allergies more seriously. The fact is that few of the food allergies not only lead to adverse reactions but also may be life-threatening.
So, what is food allergy and how is it caused?
You may think that any negative reaction to food is called as allergy. But, that's not true. Your body can have several negative reactions to food, but all of them need not be allergic reactions.
Food allergies are reactions towards certain food components that involve the immune system. They occur when the cells of the immune system recognize a substance in food as harmful and try to destroy it. These substances which trigger an allergic reaction in the body are called allergens and the most common allergens in foods are proteins.
Is food allergy and food intolerance the same?
People often get confused between food allergy and food intolerance. Food intolerance is when your body is unable to properly digest a certain foods because of an enzyme deficiency (eg: Lactose intolerance where people are intolerant to milk and milk products). Food allergies, on the other hand, have nothing to do with enzymes. They are caused due to an immunological reaction. The symptoms of food intolerance do not develop instantly as in case of food allergy and may not be life-threatening.
Read more about causes, symptoms, diagnosis and treatment of anaphylaxis.
What are the most common food allergies?
While you may be allergic to almost any food you eat, common foods such as egg, wheat, peanuts, milk and chickpeas are related to almost 90% of food allergies found in India. The incidence of these allergies varies across India depending on food consumption in different regions, religions and cultures.
1. Wheat and corn allergy:
These allergies are common in children and adults who consume wheat and wheat products such as bread, cookies, malt products, alcoholic beverages, processed meat and seasonings. According to a report published in the Indian Journal of Medical Research (IJMR), wheat allergy is becoming more common in North India due to the varieties of wheat crops grown and the increased use of pesticides. It is found in both children and adults. If it develops during childhood, it lasts forever.
How is it recognized?
On eating anything that contains wheat and corn, if you notice the below symptoms you could be suffering from the allergy.
Why should you take it seriously?
Gluten allergy can cause serious allergic reactions leading to complications like chest pain and tightness, difficulty in breathing and swallowing, swelling of throat, pale skin and very low BP.
2. Allergy due to milk and milk products:
These allergies are common in children and adults who consume cow milk and milk products like ice-cream, lassi, buttermilk, cheese and yoghurt. In India, milk allergy is commonly found in metropolitan cities like Delhi, Bangalore, Madras and Mumbai where the use of milk powder, imported from Europe to provide reconstituted milk, and tetra pack milk or pooled milk is increasing. According to 1990 estimates, milk allergy was found in less than 5% of Indian population. But as of 2013, more than 50% of people residing in these cities now suffer allergies and health problems caused by milk and milk products.
There are more than 25 different components in milk which have been identified by researchers as potential food allergens. The protein that usually triggers an immunological reaction in milk is S1-caesin. Deterioration of milk quality is also one of the reasons why milk allergy is becoming common in India. Contamination of milk due to widespread use of chemical pesticides on cow feed has increased the chances of allergic reactions to milk.
How is it recognized?
Common symptoms include wheezing, vomiting or development of an evident red, itchy rash on skin called as hives. Other symptoms which may take a while to fully develop include:
Children and adults with milk allergy rarely develop complications. But they more likely to develop allergies to other foods such as peanuts or eggs which can lead to complications.
3. Egg allergy: These allergies are common in children and adults who consume eggs in any form and egg products such as cakes, pastries, baked foods, mayonnaise, pasta, soups and wine, which contain eggs. Egg allergies are most common in infants between 6 and 15 months of age. It is believed that egg whites cause more allergy than the yolks. In rare cases, people might be allergic to both.
How is it recognized?
On eating egg or products containing eggs, if you notice the following symptoms you might be suffering from allergy to eggs.
Why do you need to take it more seriously?
Egg allergy can lead to serious allergic reactions (anaphylaxis). Symptoms such as severe stomach pain and cramps, increased pulse rate, dizziness or loss of consciousness can indicate a medical emergency.
4. Allergy due to peanuts and other tree nuts such as walnuts, almonds and cashewnuts:
Allergies are common in children and adults who consume plain roasted peanuts and products containing peanuts. About 33% of individuals who have peanut allergy may also show allergic reaction to other tree nuts. According to a report published in the Journal of the Indian Medical Association, peanuts are the most common food allergen in India. Peanut allergy is seen in both adults and children. It is observed that about 9% percent of children suffering tree nut allergy and 20% of children having peanut allergy eventually outgrow their allergy as adults.
Researchers believe that exposing peanuts to high temperature while roasting alters their protein structure which increases the likelihood of allergic reaction. Chances of peanut allergy increase in people having other forms of allergy such as asthma, eczema and hay fever.
How is it recognized?
Common symptoms of peanut allergy include:
Why do you need to take it more seriously?
Peanut allergy is the most common cause of food-induced serious allergic reaction (anaphylaxis) leading to a life-threatening condition. Complications include:
Diagnosis and tests for food allergies:
Many people think that food allergy does not require medical help if they avoid eating those foods. By simply avoiding foods suspecting that you might be allergic to them may deprive you of essential nutrients and could be also be dangerous if you are allergic to some other foods. As mentioned earlier, every negative reaction to food might not be an allergic reaction therefore a diagnostic test must be performed to confirm an allergic reaction.
In a scratch-the-skin test, a dilute suspension of the food suspected to cause an allergy is placed on the surface of skin on forearm or back. The skin then is scratched with a needle to observe for immediate changes such as swelling or redness. A positive skin test confirms a local allergic reaction to the food.
In certain situations, such as extensive eczema, skin tests cannot be performed as it may lead to dangerous consequences. In such cases, the doctor may recommend blood tests such as the RAST (Radioallergosorbent assay) and the ELISA (Enzyme-linked immunosorbent assay).
Both these tests detect the presence of food-specific IgE antibodies in the blood of patients. They are expensive and the results are not readily available.
Sometimes, the doctor may suggest you to eliminate certain foods from the diet for a few weeks to check whether the symptoms subside. This method is usually combined with a skin or blood test. In some instances, the doctor may ask you to gradually reintroduce small quantities of those foods to your diet. If the symptoms recur, then you are certainly allergic to that food.
An oral challenge test is usually done when eliminating suspected food from the diet does not give conclusive results. In this test, foods suspected to induce allergy along with other foods are given to the patient in the form of capsules. Both the patient and the doctor are unaware of which capsules contain the suspected allergens. The doctor observes whether an allergic reaction has occurred. Oral food challenge confirms a food allergy.
Treatment of food allergies
Special diets are the most commonly used treatment for food allergies. Medical emergencies due to complications are handled by treatment with an epinephrine (adrenaline) injection. But, certain medications and supplements are also used to deal with food allergy symptoms.
Precautions and risk management for food allergies:
If you feel you or your child is allergic to a certain food:
Read more about causes, symptoms, diagnosis and treatment of food allergy.
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