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Allergy - the Term Explained in a Scientific Way

Written by 
Dr. Parmar Parin Niranjanbhai
 and medically reviewed by iCliniq medical review team.

Education: MBBS, MD Pediatrics

Professional Bio:

Dr. Parmar Parin Niranjanbhai is an Asthma Specialist dealing with pediatric allergies and child health. He obtained his MBBS degree from B.J. Medical College, Ahmedabad, in 2007, and his MD in Ped... 

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Published on Jan 30, 2017 and last reviewed on Sep 16, 2023   -  5 min read


Due to the widespread use of the term allergy, there are many misconceptions about allergic disorders among patients and the general population. This article aims to explain allergy in a scientific way, but in simple language and with examples.

Allergy - the Term Explained in a Scientific Way


Allergic disorders are very common and are increasing worldwide. The term allergy is also very commonly used by doctors, patients, and the general population. However, the liberal use of the word allergy has created many misconceptions and confusion about allergies.

What Is Allergy?

Allergy is an immunological disorder characterized by an abnormally exaggerated response by the immune system towards harmless substances, which usually contain proteins. Two things which have to be cleared up are:

  1. An allergy is towards harmless substances, say milk, wheat, peanut, house dust mites, molds, pollens, etc.

  2. It is an immune reaction, and it has nothing to do with external things and conditions, but it is the immune system that is working abnormally.

If one experiences exacerbation of asthma after exposure to cigarette smoke, one is not allergic to cigarette smoke and the immune system does not play an active role against smoke. Because cigarette smoke is not a harmless substance and they worsen the allergy rather than causing it. Smoke, strong smells, air pollution, etc., can worsen asthma or respiratory allergies by causing irritation rather than causing the allergy itself.

If one develops itching and rash after consuming artificially flavored milk, but has no problem drinking unflavored natural milk, then the reaction to the flavored milk is most likely due to the chemical properties of the added flavor or essence. Such a reaction is not a true allergy, and one's immune system is usually normal.

What Is an Allergic Reaction?

Allergic reaction is the way how our body reacts to the allergen. There is a chain of events that occur during the allergic reaction. The first thing that happens after being exposed to a specific allergen is the production of IgE antibodies by our body. These antibodies detect the allergen and release the chemical histamine, and this chemical acts on the skin, eyes, nose, and different parts of the body to cause symptoms of allergies.

What Are the Substances That Commonly Cause Allergies?

A substance that is responsible for the allergic reaction is called the allergen. Usually many allergens are harmless to most people. The most common food allergens seen in susceptible people are the following:

  • Fish.

  • Soy.

  • Milk and milk products.

  • Peanuts.

  • Wheat.

  • Eggs, especially the whites.

  • Crustacean shellfish.

Some of the other common allergens are:

What Are the Common Symptoms of an Allergy?

Inflammation and irritation are the first signs of an allergic reaction. But the symptoms depend on the types of allergens causing it. Here are some of the symptoms of allergy:

Allergy to Food Substances:

  • Vomiting.

  • Diarrhea.

  • Swelling of the lips, tongue, and face.

  • Rashes.

  • Stomach cramps.

  • Itchiness in the mouth.

  • Shortness of breath.

  • Tingling sensation in the mouth.

  • Itchiness in the mouth.

  • Shortness of breath.

Allergy to Dust and Pollen:

  • Runny nose.

  • Itchy nose.

  • Blocked or congested nose.

  • Swelling of the eyes.

  • Watery eyes.

Allergic Reaction After Insect Stings:

  • Swelling at the site of the sting.

  • Itchy skin.

  • Hives.

  • Shortness of breath or chest tightness.

  • Drop in the blood pressure.

  • Dizziness.

  • Cough.

  • Wheezing.

  • Restlessness.

Allergy to Medications:

  • Wheezing.

  • Rashes.

  • Itchiness.

  • Swelling of the face, lips, and tongue.

One of the severe forms of symptoms are anaphylaxis symptoms. Anaphylaxis is an emergency and a life-threatening condition. Some of the symptoms include:

  • Wheezing.

  • Difficulty breathing.

  • Sudden fall in blood pressure.

  • Dizziness.

  • Loss of consciousness.

  • Changes in heart rate.

  • Hives and flushing.

Can Children Have Allergies?

Allergic disorders in children include allergic rhinitis, allergic asthma, allergic conjunctivitis, atopic dermatitis, food allergies, allergic urticaria or angioedema, anaphylaxis, drug allergies, latex allergy, and miscellaneous ones.

How To Diagnose Allergy?

The different types of allergy tests are:

  • Skin test.

  • Blood tests.

Skin Test:

A skin test is performed by applying a small amount of suspected allergen to the skin, and observing the reaction. There are a number of skin tests like:

A skin test is effective for diagnosing allergies caused due to food substances, mold, pollen, and Penicillin allergies.

Blood Test:

A blood test is done to check for antibodies against a possible allergen. This blood test is done if the skin test is not possible or not effective.

What Is the Treatment for Allergies?

The treatment for allergies include:

  • Medications.

  • Immunotherapy.

  • Emergency Epinephrine.

The first and foremost thing is to identify and avoid allergens. This is one way to prevent an allergy towards a known allergen.


Medications that are used to treat allergies are:


Antihistamines block the chemical that is causing the symptoms during an allergic reaction. Some of the antihistamines include:


Decongestants are recommended for temporary relief of nasal and sinus congestion. Some of the decongestants are:

  • Pseudoephedrine.

  • Oxymetazoline.

  • Tetrahydrozoline.


Corticosteroids relieve the symptoms of allergy. Some of the corticosteroids are:


In this treatment method, the body’s immune system is trained not to react to these allergens. It is done when other treatment options are not effective. It is given as shots or sublingual immunotherapy (SLIT).

Emergency Epinephrine:

If you have severe allergic reactions, then emergency Epinephrine shots should be given to reduce the symptoms until the emergency treatment is done. People should carry two epinephrine auto-injectors along with them at all times. By using an auto-injector, a measured dose of Epinephrine can be administered within a few minutes of any severe symptoms.

How To Prevent Allergies?

There is no way to cure an allergy, but there are ways you can prevent it. They include:

  • Get allergy testing done to determine which substance is responsible for the allergic reaction.

  • Follow some measures to avoid exposure to the known allergens.

  • Inform your friends and family about the allergy you have.

  • Always carry two auto-injectors and have detailed knowledge on how to use them correctly.

Frequently Asked Questions


How Can Allergies Be Controlled Fast?

Antihistamines help in controlling allergic symptoms. Epinephrine pens can be used to control and stop allergic reactions immediately. Other methods to control allergy are nasal saline irrigation, taking Vitamin C, wearing a mask, etc.


What Are the Common Types of Allergy?

There are various types of allergies. The most common types of allergies are asthma, skin allergy, drug allergy, food allergy, dermatitis, rhinitis, etc.


Which Is the Best Allergic Medication for Children?

The best allergy medicine for children is an antihistamine tablet named Cetirizine. The Epinephrine pen can be used for children who weigh above 30 kgs. The allergic medication can be given for children above six months, and the dosage varies based on the age and weight of the child.


When Does Allergic Medicine Start to Work?

Different types of allergic medicines start working at different times, oral antihistamines start working 1 to 2 hours after intake, antihistamine sprays start working within 15 minutes, nasal steroids start working only after a week.


How to Differentiate a Rash Due to a Food Allergy?

Different types of skin rashes have different appearances. A food-allergy-induced rash will appear as raised skin bumps that are red or pink in color. They will be round in shape with red flares around them.


What Are the Symptoms of Severe Allergy?

The severe allergy symptoms are swelling, skin rashes, itching, runny nose, itchy eyes, stomach cramps, etc. These symptoms lead to difficulty in breathing, swallowing, etc.


Will Allergies Cause Hot Flashes and Body Aches?

Symptoms caused by allergic reactions vary from person to person and also change based on the type of allergy. Some allergies such as hay fever, allergic rhinitis may cause the development of hot flashes and body aches. Some allergies might also give a sick feeling.


Do Seasonal Allergies Affect the Immune System?

Seasonal allergies will occur repetitively, and this will lead to the intake of anti-allergic drugs for a long period of time. Intake of anti-allergic drugs for a long duration will weaken the body’s immune system hence making the individual more susceptible to viral, bacterial, or other infections.


How Do Vitamins Help in Allergic Reactions?

Vitamin C plays an important role in controlling allergic reactions. They act as a natural antihistamine. Vitamin D also helps in controlling allergic reactions.


How Does Turmeric Reduce Allergic Reactions?

Turmeric acts as an antihistamine. They reduce the release of histamine, thus controlling the allergic reactions caused by allergens.

Last reviewed at:
16 Sep 2023  -  5 min read

Dr. Parmar Parin Niranjanbhai

Dr. Parmar Parin Niranjanbhai

Pediatric Allergy/Asthma Specialist


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