Allergy Information

  • What is an allergy?
  • Can people outgrow their allergies?
  • Can children inherit their parents' allergies?
  • How do antihistamines work?
  • Are all oral antihistamines available on the market the same?
  • Do antihistamines efficacy decline with time?
  • Why choose an antihistamine with an added decongestant?
  • Is hay fever is caused by hay?
  • Are flowers a major cause of allergies?
  • Do shorthaired pets cause allergies?
  • Is there a link between climate and allergies?

What is an allergy?

An allergy is a super-sensitivity to allergy triggers called allergens. Common airborne allergens include pollen from trees, grasses and weeds, molds, animal dander, dust and dust mites.

Allergies can have a big impact on your daily activities. You may be constantly fatigued, irritable, or just not feeling well. People with allergies often have difficulty concentrating, which can affect performance and even lead to absence from work or school. Many allergy sufferers have to give away pets, avoid foods they enjoy or curtail their outdoor activities. Allergic rhinitis or “hay fever” is one of the most common types of allergy. Typical symptoms of allergic rhinitis include sneezing, stuffy or runny nose, itchy or watery eyes, itchy throat and headaches.

Other types of allergic reactions include asthma, eczema and hives.

Skin rashes and hives may appear as a result of something you touch, eat or drink. In the case of a severe reaction, symptoms may be accompanied by an upset stomach, cramps, difficulty breathing or swallowing, nausea or other allergic symtoms.

Can people outgrow their allergies?

Most people grow into allergy, not out of it. Although some people can have fewer symptoms from certain substances simply by avoiding them, it is nearly impossible to avoid exposure to certain pollens, molds and dust. Repeated exposure to these allergens can cause someone to suffer from allergies his or her entire life.

Can children inherit their parents' allergies?

Allergies tend to run in families but other factors may come into play. A child's chances of developing allergies are about 50% if one parent has allergies and increase if both parents have allergies.

Individuals may develop allergies even though neither parent has ever had an allergy. Many experts also believe that early exposure to a potential allergen may make a person more likely to develop an allergy to it later in life.

How do antihistamines work?

When you are allergic to an indoor or outdoor allergen, your immune system releases a chemical substance inside your body, called histamine. Once histamine is released, it attaches to histamine receptors, and it is this interaction that triggers allergy symptoms. The antihistamine blocks histamine from attaching to the histamine receptors, and this is why antihistamines such as Claritin® relieve allergy symptoms.

Are all oral antihistamines available on the market the same?

There are many different antihistamines available on the market. They are all effective but differ in their side effect profile. Some are non-drowsy (second generation) while others may cause drowsiness (first generation).

A study concluded that first-generation antihistamines « can negatively affect mood, sleepiness, alertness, and cognitive and psychomotor function in adults and children1 ». As a result, these antihistamines can interfere with performance and safety, even when taken the night before.

Newer second-generation antihistamines, such as Claritin®, have the benefit of being non-drowsy and have a longer duration of action than first-generation antihistamines. Therefore, it is not surprising that many experts2 recommend non-drowsy antihistamines over first-generation antihistamines for the management of allergic rhinitis.

1Gary, KAY, The effects of antihistamines on cognition and performance. Journal of Allergy and Clinical Immunology, Volume 105, Issue 6, Pages 622 - 627.

2T. CASALE, et al. First do no harm: Managing antihistamine impairment in patients with allergic rhinitis, The Antihistamine Impairment Roundtable Journal of Allergy and Clinical Immunology, Volume 111, Issue 5, Pages S835 - S842.

Do antihistamines efficacy decline with time?

There is no evidence that the effectiveness of antihistamines declines with time. Therefore, Claritin® is expected to always provide you with the same effective relief.

Why choose an antihistamine with an added decongestant?

Nasal congestion is a symptom that affects many allergy sufferers and is often associated with poor sleep quality, which can lead to decreased learning ability and productivity, as well as reduced quality of life.

For those who suffer from sinus and nasal congestion, it is important to treat allergies with a product that combines a decongestant and a non-drowsy antihistamine. We recommend using a product such as Claritin® Allergy + Sinus.

Is hay fever is caused by hay?

The popular term “hay fever” dates back to 1828 when a British physician noticed that his allergy symptoms worsened during the British haying season. We now know that hay itself does not cause allergies.

Are flowers a major cause of allergies?

Despite what many people think, roses and many other fragrant, colourful flowers are not likely to cause allergies. Pollen from flowers is usually too heavy to stay airborne and requires insects to move it to another flower.

Do shorthaired pets cause allergies?

Pet allergies are not caused by fur, but by animal dander, a protein found in the animal's saliva or skin; so fur length has no effect on allergies. Cats may cause more allergy problems than dogs simply because they tend to lick their fur a lot, spreading the protein onto their coats.

Is there a link between climate and allergies?

In a recent article published in the Journal of Allergy and Clinical Immunology,1 the link between global climate change and increases in the prevalence and severity of asthma and related allergic diseases has been highlighted.

It seems that climate change affects air quality by boosting both air pollution and pollen concentration, which exacerbates asthma and respiratory allergic responses.

Warmer temperatures lead to longer pollen seasons, and increased ambient CO2 speeds up some plants' development and may cause them to be more allergenic.

1 Katherine M. SHEA, Clinical review in allergy and immunology: Climate change and allergic disease, Journal of Allergy and Clinical Immunology, Volume 122, Issue 3, Pages 443 - 453.