Allergic Rhinitis

What is allergic rhinitis?

Allergic rhinitis, also known as hay fever, is caused by the body’s immune response to an environmental trigger.

What are some other types of rhinitis?

Other less common types of rhinitis include:

Atrophic rhinitis

In atrophic rhinitis, the natural mucosal membrane is thinned out and the glands that secrete mucus and participate in mucus clearance are lost. This leads to secondary infections and persistent crusting of the nose.

This is a rare condition that occurs in those who have undergone aggressive surgery to the nasal cavities.

Vasomotor rhinitis

Vasomotor rhinitis is a condition where there is chronic rhinitis in the absence of an identifiable allergy.

Dilation of blood vessels in the nose is partly controlled by the autonomic nervous system. It is believed that an oversensitivity of this autonomic nervous system can cause vasomotor rhinitis. In some cases, the trigger may be a change of temperature or the presence of a chemical stimulant like strong perfume or chemical fumes.

What are the symptoms of allergic rhinitis?

Symptoms include:

• Blocked nose
• Runny nose
• Post-nasal drip
• Watery and itchy eyes
  

These occur after exposure to the allergen. For example, walking into a dusty room may cause such symptoms to develop.

What are some common triggers of allergic rhinitis?

How is allergic rhinitis diagnosed?

There is often a history of other allergies and sensitive skin, and some people may also have asthma.

A skin prick test may be able to identify the offending allergen (substance that triggers the allergic response). It is a simple test performed in the clinic.

In a skin prick test, a small area of skin, usually on the forearm is used to test for allergies to various allergens. A small amount of allergen is then applied to the skin and the area observed for a positive reaction.

By identifying the allergen, severe or recurrent attacks can be reduced by avoiding or minimising subsequent exposure to the allergen. Common allergens include dust mites and pollen.

How is allergic rhinitis treated?

Treatment of allergic rhinitis is aimed mainly at reducing the severity and frequency of attacks.

Methods of management can be divided into:

Environmental control

Changes to the living environment will have to be made to avoid the allergens that trigger attacks. For example, frequent cleaning of living areas and replacing items such as carpets or stuffed toys may reduce the amount of exposure to dust mites in the house.

Medical therapy

Medical therapy is directed at controlling symptoms and reducing the allergic response.

In cases where symptoms are intermittent, antihistamines may be prescribed. Where attacks are frequent, a nasal steroid may also be added. Nasal steroids are widely used because they are effective for long-term control of symptoms and are safe for long-term use as they have a topical action and very little of the steroid actually gets absorbed by the body.

Surgical therapy

Surgical therapy may be useful where there are anatomical abnormalities such as a deviated nasal septum, or inferior turbinate hypertrophy.

Surgery may improve the symptoms of congestion and blockage, but may not have any impact on the other symptoms such as runny nose or itchy eyes. Nasal steroids may still have to be used to control these symptoms.

Immunotherapy

It is also suitable for a select group of people with severe, prolonged symptoms that do not respond to conventional therapy.

In immunotherapy, the body’s immune system is modulated to reduce the response to the allergen, thus reducing the severity of symptoms. This is a slow process and will require injections or self-administered drops taken regularly over a period of 1 to 3 years.