What is Allergy?

Allergies are over-reactions of the body to substances that may not normally occur. So we can develop allergic reactions to environmental substances such as dust mites, pollens and pet dander. We can also become sensitive to foods like peanuts, seafood and milk.

The incidence of allergies is increasing affecting up to 40 % of the population. Children are more prone to developing allergies.

What is the mechanism of allergy?

If one is allergic to dust mite, the dust mite is called the allergen. The body overproduces an antibody called IgE to “neutralize” the allergen. This is an allergen specific response. The IgE then trigger a host of reactions that results in symptoms such as runny and itchy nose and eyes; blocked nose; sneezing and skin rash. The majority of these symptoms is caused by histamine.

How are allergies classified?
Allergies can manifests in a variety of ways and affect different organs. Depending on the organ involved or their causes, they are called differently.

    • Allergic rhinitis (Nose)
    • Allergic Conjunctivitis (Eyses)
    • Allergic Asthma (Lungs)
    • Food Allergies
    • Drug Allergies
    • Skin Allergies


Of these the most common are those involving the respiratory system such as allergic rhinitis and asthma.

What are the allergens (Causes) involved in allergic rhinitis and allergic asthma?

In this part of the world, house dust mites and pets (Cats and Dogs) are the most common allergens.

How does allergy affects our quality of life?

For those of us who suffers from allergies, we can be miserable during the time when allergies affect us. We can be lethargic, unable to concentrate and generally feels lousy. Studies have shown that allergies can affect the ability of children to perform they are not managed. This is especially crucial in a competitive environment like Singapore

How do we diagnose allergic rhinitis and allergic asthma?
For allergies to be appropriately treated and controlled, it is important that the specific allergen(s) causing the allergic symptoms be identified. The first step is a detailed history and physical examination to confirm the symptoms of allergy. The methods of determining the incriminated allergen include using skin tests and blood tests.

I am allergic to house dust mite. What can I do?

If there is no exposure, there will be no allergies. This is ideal, however we cannot avoid dust mite completely no matter how hard we try. By keeping our house clean, regularly changing bed sheets and covers, we can minimize the exposure and hence symptoms.

If despite these measures, we are still symptomatic, medication may be needed.

Antihistamine– This blocks the reaction of histamine bring about relieve of symptoms

Steroid Nasal Sprays & Inhalers – This suppress the allergic response.

Oral Steriods – Oral steroids is used in more severe allergies but long term use has significant side effects

Antileucotrienes – This is helps in lowering the allergic response.

Saline nasal wash – Saline sprays such as sterimar helps to remove the allergens from the nose and clear obstructing mucus. This can be an adjunct to the other medication.

Is there a cure for allergies?
Medication as those listed above only blocks the symptoms of allergies but does not affect the underlying reaction. Allergen immunotherapy consists of administration of gradually increasing quantities of an allergen extract to a patient who has been proven to be allergic and to develop symptoms due to that particular allergen. As it targets the root cause, immunotherapy can alter the natural course of allergy. The administration of the immunotherapy can be by injection or by drops (Sublingual Immunotherapy) under the tongue. These have proved to be effective in allergic rhinitis and allergic asthma.

Allergies can be managed and even cured. We need not live under the shadows of allergies. What is important is that we recognize the symptoms and take appropriate actions.

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This article was published in EzyHealth August 2008

Senior Ear Nose Throat & Allergy Consultant
Centre for Ear Nose Throat Allergy & Snoring

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