Most allergic rhinitis is seasonal, occuring in the warmer months and stopping when outdoor temperatures reach freezing. Typical symptoms include nasal congestion, itchy red eyes, runny nose, sneezing, wheezing and cough. Allergic rhinitis is more common in children with other atopic diseases such as asthma and eczema. Treatment of allergic rhinitis includes medications such as antihistamines and also avoidance of potential allergens.
What causes allergies?
The simple answer is "allergens." These are things like mold spores, dust mite parts, pollens, and cat skin flakes that cause allergy symptoms. It is not entirely known why some children are more sensitive to allergens. One idea called the "hygiene theory" proposes that children in cleaner environments (with chlorinated water, antibacterial soaps and air filters, for example) are not given the opportunity to "train" the immune system to tolerate allergens early in life. This may help explain why industrialized nations such as the United States has more children with allergic rhinitis, asthma and eczema when compared to other less-modern societies.
What part of the immune system is responsible?
An over-reaction of mast cells, T-lymphocytes and eosinophils cause inflammation in the tissue lining the nose, throat and airways.
What are some common allergens?
- Mold spores
- Dust mite parts
- Pollens (trees, grasses, plants)
- Cat skin flakes (dander)
What are the symptoms of allergic rhinitis?
- Itchy, runny nose
- Itchy, red eyes (sometimes with eyelid swelling)
- Nasal congestion
How are allergies diagnosed?
The history and timing of the symptoms is usually enough to make a diagnosis. Upper respiratory tract infections can cause similar symptoms, however allergic rhinitis symptoms persist longer than an infection and are not associated with fever.
Physical exam by a doctor may show:
- Red, watery eyes
- Swollen, pale mucosa in the nose with clear drainage
- Allergic shiners (a purple hue under the eyes)
- Nasal crease (a skin crease on the bridge of the nose from frequent itchy nose rubbing)
- Mouth breathing and a "nasal" voice (due to nasal congestion)
Skin testing - In some cases, skin prick testing can be performed by an allergist to help determine which allergens may be responsible for the symptoms. This is done by taking a solution of an allergen, dipping a needle in the solution, and pricking the skin (usually on the back) of the child. If an allergy is present, then the area will become red and swollen. The skin prick test can check for multiple possible allergens at one time. Allergy medicines must be stopped several days before skin testing, and eczema may make testing inaccurate.
RAST (radioallergosorbent test) - This is a blood test that check for levels of antibodies (IgE) to specific allergens.
How are allergies treated?
Avoidance of possible allergens. In some cases this may include:
- Remove drapes and carpeting in the house
- Avoid sleeping on sofas
- Cover bedding with dust mite proofing material
- Avoid sleeping with stuffed animals and pets
- Close bedroom windows (if pollens are suspected)
- Use air filters in the home
- Remove pets from the home
Oral antihistamines such as fexofenadine (Allegra), desloratidine (Clarinex), and loratidine (Alavert, Claritin) are often helpful. These medicines are less sedating than diphenhydramine (Benadryl) and hydroxyzine (Atarax). Diphenhydramine (Benadryl) is the active ingredient in many "sleep pills."
Intranasal corticosteroids such as fluticasone (Flonase), mometasone (Nasonex), triamcinolone (Nasocort), and budesonide (Rhinocort) are often used for persistent or severe allergic rhinitis. Side effects of intranasal steroids are less than that seen with oral corticosteroid therapy.
What are the complications of allergic rhinitis?
Allergic rhinitis is more common in children with eczema and asthma. Possible complications include:
- Cough and sore throat (from post-nasal drip)
- Ear infections
Last Updated (Monday, 22 June 2009 11:03)