Allergic rhinitis

What is rhinitis?

The nose is lined with a membrane that produces mucous. The mucous, a thin clear liquid, traps small particles and bacteria that are drawn into the nose as a person breathes. Rhinitis is a swelling of the mucous membrane due to irritation or congestion and results in a runny nose, itching, and sneezing. Irritants in the environment like cigarette smoke, chemicals, temperature changes, stress, exercise, or other factors may provoke rhinitis in susceptible people, such as those who have allergies.

What are the causes?

Allergic reactions in the nose lead to release of certain chemicals. One of these chemicals, histamine, causes dilation of blood vessels, skin redness, and swollen membranes. This leads to symptoms of so-called allergic rhinitis.

Allergens in the house, such as house dust mites and pet dander cause allergic rhinitis. Moulds growing on wallpaper, upholstery, carpeting, and house-plants are also allergens. One plant can release one million pollen grains a day. Other grasses and trees that release very small pollen grains also cause allergies. Grass allergies are experienced more in the late afternoon; and mould spores may peak on dry windy afternoons or on damp or rainy days in the early morning.

What are the symptoms?

Symptoms of allergic rhinitis include frequent or repetitive sneezing, a runny or congested nose, and itching in the nose, eyes, throat, or roof of the mouth. Affected people may also have plugged ears, a decreased sense of smell, postnasal drip, or sinus headaches.

Children with family members who are allergic are at highest risk, but allergies can develop in anyone. Although allergies often appear first in childhood, they may develop at any age.

Lifestyle factors include wall-to-wall carpeting, cat ownership and dampness in the home. Spending more time indoors for watching television may also be responsible for allergies. Seasonal allergic rhinitis tends to diminish as a person ages. People with allergic rhinitis may be at higher risk for other allergies, including food or latex allergies.

What are the complications of rhinitis?

Allergic rhinitis is associated with ear infections due to blockage of the eustachian tube, which connects the middle ear with the nasopharynx (space at the back of the throat, behind the nose). It can also cause headaches and also affect a child's sleep, concentration, hearing, appetite, and growth. Structural abnormalities or chronic nasal obstruction from year-round allergies can even affect a child's appearance.

How is it diagnosed?

The doctor will ask a number of questions, including whether a family history of allergies is present. The timing of symptoms helps the doctor make a diagnosis. Rhinitis that appears seasonally is almost always due to pollens and outdoor allergens. The doctor will usually examine the inside of the nose with an instrument called a speculum to look for redness and other signs of inflammation. The doctor will also usually check the eyes, ears, and chest.

A skin test is a simple method for detecting common allergens in people who are candidates for allergy shots (immunotherapy). Small amounts of suspected allergens are applied to the skin with a needle prick. A new intra-dermal test that works by injecting a drop of the allergen into the skin may be more sensitive than the standard puncture test. If an allergy is present, a red, swollen area forms within 20 minutes.

What is the treatment?

The goal of treatment is to reduce allergy symptoms caused by the inflammation of affected tissues. Most cases of mild allergic rhinitis require little more than reducing exposure to allergens and using a nasal wash. A nasal wash helps in removing mucous from the nose. A saline solution can be purchased at a chemist shop or made at home by mixing one teaspoon of salt and a pinch of baking soda in a pint of warm water.

Decongestants relieve nasal congestion and itchy eyes. Antihistamine tablets relieve sneezing and itching, and can prevent nasal congestion before an allergy attack. Antihistamines cause drowsiness so it is important to avoid driving or working with machinery after taking them. Corticosteroid and sodium cromoglycate nasal sprays reduce inflammation and are effective in treating allergic rhinitis symptoms.

Immunotherapy (allergy shots) may be given to people over seven whose allergies are severe and do not respond to medication. The object of these shots is to make the immune system tolerant to the allergen. However, these allergy shots are of limited use if the affected person is allergic to a large number of allergens. Surgery may be needed for certain cases of mechanical obstruction, such as deviated septum or polyps.