Everything You Need to Know About Allergies

If you have allergies, you are not alone. Millions of people around the world suffer from allergies1 and experience symptoms including runny nose and sneezing, congestion, and red, itchy eyes. Skin allergies, on the other hand, can manifest in itchy skin, redness, rashes or hives .

While allergies such as a skin allergy , or allergic rhinitis are certainly irritating, they can be managed by learning more about them. Read on to learn more about allergy triggers and methods of relieving symptoms.

What are Allergies?  

An allergy is a reaction by the body’s immune system to certain substances.2 The result of this reaction are the various allergy symptoms that you experience, like sneezing, or itching. These are also known as allergic reactions. Allergies are varied and include skin allergy, dust allergy, pollen allergy, and more.

Let’s take a more detailed look at what happens in the body during an allergic reaction.

Immune System Overreaction

Your immune system’s job is to protect your body against harmful “invaders” like viruses and bacteria by attacking and destroying them. But sometimes, the immune system overreacts to typically harmless substances like dust or pollen (known as allergens) – and it is this that causes an allergy to develop.

When the immune system is triggered by allergens, it produces antibodies called Immunoglobulin E (IgE).3 These travel to cells, which in turn produce chemicals known as histamines. Histamines, which are part of the body’s defense system, work to eliminate the allergens. In the process, they cause symptoms typical to an allergic reaction, including sneezing, runny nose, rashes and congestion.4

Every type of IgE has a “radar” for a specific kind of allergen 3. This is why some people might only be allergic to pollen, or only have a skin allergy, while others might have multiple allergies because they have more types of IgE antibodies.

Common Allergens

Substances that trigger allergies are called allergens. Some of the more common ones include5:

  • Pollen: These come from the flowers of grass, plants, and trees. An allergy to pollen is also known as hay fever .
  • Dust Mites : These are microscopic pests. Hundreds of thousands of these mites may live in bedding, carpets, curtains, pillows and mattresses. They feed on the dead human skin cells that are found in dust. The allergen these mites emit is their feces and body parts.6
  • Animal Dander: These are tiny flakes of skin shed by animals, especially those with fur like cats and dogs.
  • Food: Common food allergies include nuts, fruit, shellfish, eggs and milk.
  • Insect bites and stings
  • Latex: This is the form of rubber that is used to make gloves and condoms, and can cause skin allergy.
  • Mold : This is a type of fungi that grows in warm, damp places in homes. The spores they release can trigger allergies.
  • Household chemicals: Some of these, including those in detergents and hair dyes, could trigger a skin allergy.

How are Allergies Developed?

Anyone can develop an allergy at any stage in their life.

The development of allergies is complex and thought to be partly genetic7 and partly due to environmental factors8. This means that certain allergies, including a skin allergy like dermatitis or urticaria , or food allergies, can be inherited. These are known as atopic allergies.

But just because the parent/s have allergies, doesn’t mean that the child will definitely inherit the condition; however, there is a higher possibility that they will.

Other allergies can be caused by environmental factors like pollution or pollen , or even pet dander and mold spores that can carry through the air or come into contact with the skin.

When an allergy causes inflammation in the inside of the nose, leading to runny nose or congestion, sneezing, and itchiness, it is known as allergic rhinitis . Triggers of allergic rhinitis include pet dander, dust, and pollen.

Additionally, some people can develop allergies to drugs and medications such as penicillin. Eye allergies are also common.

A medical specialist called an allergist may help diagnose your allergies and can then advise you on an allergy treatment and prevention plan.

Signs and Symptoms of Allergies

Common symptoms of an allergic reaction include 9:

  • Itchy, runny or blocked nose (allergic rhinitis)
  • Red, watering, itchy eyes ( conjunctivitis )
  • Shortness of breath, cough, wheezing
  • A red, raised rash ( hives )
  • Swelling of the lips, tongue, eyes or face
  • Dry, red or cracked skin

The most severe form of allergic reaction is known as anaphylaxis . This can be life threatening without quick medical intervention. Symptoms include swelling of the throat and mouth, inability to breathe, dizziness, and confusion. Anaphylaxis requires an injection of epinephrine. If you don’t have this medication with you, then you must head to an emergency room immediately.

Alleviating Symptoms of Allergies

One way of alleviating allergy symptoms especially related to allergic rhinitis and skin allergy, is to take an antihistamine , such as loratadine. An antihistamine works to counter the effect of the chemical histamine in your body, which is responsible for allergy symptoms.

Loratadine is a non-drowsy antihistamine that helps provide relief for symptoms caused by allergens such as dust, pollution, pet dander , mold , and pollen .

Keep in mind that antihistamines are not used to prevent or treat a serious allergic reaction like anaphylaxis -- you should have a treatment plan for this given to you by your healthcare provider and you should always stick to this plan.

You can also take steps in your home, as well as when you head outdoors, to prevent exposure to allergens. These include:

  • Changing your clothes or showering when you come inside. This gets rid of allergens like dust and pollen that may be on your person.
  • Deep cleaning your home once a week and performing daily quick cleans where you vacuum and clear dust off of surfaces with a damp cloth.
  • Keeping your windows and doors closed during high pollen season or when there is haze (pollution).
  • Maintaining your garden by cutting the lawn and keeping it clear of plants that could trigger allergies.
  • Tending to your houseplants by wiping down leaves to prevent dust build-up and making sure not to overwater them to avoid mold growth in the soil.
  • Washing your bedding regularly. To help reduce allergens from building up in your bedding, wash it in hot water every week.
  • If you are heading outdoors when environmental pollution levels (haze or ash fall) are high, wear a well-fitting N95 mask.
  • Always keep allergy medication like Loratadine (Claritin®) at home, and in your bag when you go out. Loratadine (Claritin®) works in as fast as 15 minutes10, is non-drowsy11,12 vs. first-generation antihistamines and cetirizine, and lasts up to 24 hours12.

ASC Ref. Code: B125P032222CS


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  3. Allergic reactions. American Academy of Allergy, Asthma & Immunology. Retrieved on December 1, 2021 from https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/allergic-reactions
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  7. Genetics of Allergic Diseases. Ortis, R. and Barnes, K. 2015. Immunol Allergy Clin North Am. Retrieved on December 1, 2021 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415518/
  8. Environmental factors and allergic diseases. 2012. Jenerowicz et.al. Ann Agric Environ Med. Retrieved on December 1, 2021 from https://pubmed.ncbi.nlm.nih.gov/23020042/
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  11. Kawauchi, H.; Yanai, K.; Wang, D.-Y.; Itahashi, K.; Okubo, K. Antihistamines for Allergic Rhinitis Treatment from the Viewpoint of Nonsedative Properties. Int. J. Mol. Sci. 2019, 20, 213. https://doi.org/10.3390/ijms20010213
  12. Haria, Malini, et al. “Loratadine.” Drugs, vol. 48, no. 4, 1994, pp. 617–637., https://doi.org/10.2165/00003495-199448040-00009.