What is the Definition of Allergy? Unraveling the Mystery

Allergy is an immune response to a substance that will harmlessly cause a reaction in others. Thus, the body’s immune system views the allergen as foreign and produces an immune response, releasing antibodies that cause the harmful reactions related to allergies. Allergies can be life-long and debilitating, which is why it’s essential to understand the definition of allergies and the science behind them.

Allergy: The Basics

Simply put, an allergy is an overreaction of the immune system to a foreign substance. This foreign substance could be a food, pet dander, pollen, or mold. When the body’s immune system encounters it, it creates what is known as an allergic reaction.

This overreaction can cause mild to severe symptoms, depending on the person’s immune system’s sensitivity. Some people may have no symptoms at all, while others may experience life-threatening reactions known as anaphylaxis.

Allergies vs. Intolerances

It’s important to note that allergies are different from intolerances. For instance, an intolerance to lactose means that the body can’t digest lactose efficiently. This results in bloating, gas, and diarrhea. Conversely, an allergy to milk means that the immune system views the proteins in milk as foreign and creates an allergic reaction.

Types of Allergies

There are several types of allergies, including:

  • Food allergies: These are allergies to specific foods like peanuts, shellfish, eggs, and wheat.
  • Seasonal allergies: These are allergies to pollen and other allergens that are present during certain seasons.
  • Insect allergies: These include allergies to bee stings or mosquito bites.
  • Drug allergies: These are allergies to specific medications or groups of medications.

The Science Behind Allergies

How Allergies Develop

When someone is allergic to a particular substance, it’s because their immune system has developed a hypersensitivity to it. This hypersensitivity means that the immune system identifies the substance as harmful and creates an allergic response. This reaction can vary from person to person, and some people may develop more severe reactions than others.

Allergy Symptoms

The symptoms of allergies can vary from person to person, but they typically include:

  • Sneezing
  • Coughing
  • Wheezing
  • Itching
  • Hives
  • Rashes
  • Swelling

Some people may also experience more severe, life-threatening symptoms such as anaphylaxis. This is a severe allergic reaction that can cause a person’s airways to close, making it difficult to breathe. If left untreated, anaphylaxis can be fatal.

How Allergies Are Diagnosed

There are several ways that allergies can be diagnosed. Your doctor may perform a skin prick test, where a small amount of the allergen is injected into the skin to see if an allergic reaction occurs. Blood tests can also be performed to check for specific antibodies to the allergens.

Managing Allergies

Preventing Allergies

The best way to manage allergies is to avoid exposure to the allergen. For example, if you’re allergic to pollen, you can avoid going outside during peak pollen times. If you have a food allergy, you can read food labels carefully and avoid foods that contain the allergen.

Allergy Medications

If avoiding the allergen is not possible, there are medications available that can help manage allergy symptoms. These include antihistamines, which block the production of histamine, a chemical that causes allergy symptoms. Decongestants can also be used to reduce nasal congestion.

Allergy Shots

Allergy shots, also known as immunotherapy, can be used to treat severe allergies. These shots contain a small amount of the allergen and are administered over time to build up the body’s tolerance to it.

Alternative Treatments

Several alternative treatments may be useful in managing allergies. These include acupuncture, herbal supplements, and probiotics. However, it’s essential to speak with your doctor before trying any alternative treatments to ensure they’re safe and effective.

The Bottom Line

Allergies are a common immune system response to specific substances. They can cause mild to severe symptoms and, in some cases, can be life-threatening. Knowing the definition of allergies and the science behind them is essential in managing and treating allergies.


  • Q. What causes allergies?
  • A. Allergies are caused by the body’s immune system’s hypersensitivity to specific substances like pollen, mold, or food proteins.
  • Q. Can allergies be prevented?
  • A. The best way to prevent allergies is to avoid exposure to the allergen.
  • Q. What are the most common allergy symptoms?
  • A. The most common allergy symptoms include sneezing, coughing, wheezing, itching, and swelling.
  • Q. Can allergies be cured?
  • A. While there is no cure for allergies, they can be managed using medications and allergy shots.


1. Mayo Clinic. (2021, March 5). Allergies. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/allergies/symptoms-causes/syc-20351497

2. AAAAI. (2021). Allergy Basics. AAAAI. https://www.aaaai.org/conditions-and-treatments/allergies/allergy-basics

3. National Institute of Allergy and Infectious Diseases. (2020, December 17). Allergies. National Institutes of Health. https://www.niaid.nih.gov/diseases-conditions/allergies

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