FAQ: Nasal Allergies
Written by Amanda Wattson, MD   
Thursday, 29 October 2009

Nasal allergies refer to the interaction of allergens with cells within the lining of the nose.

What is going on in the body?



Allergens enter through the nose. Allergens include pollens, dust, dust mites, mold spores, and animal dander. These substances interact with IgE antibody on the mast cells inside the nose. This causes discharge of histamine. Histamine causes sneezing, nasal congestion, and nasal discharge.

The mast cells also release other substances. These substances pull a group of cells, called eosinophils, into the nasal lining. The eosinophils travel into the lining of the nose over a 6- to 24-hour period. They then release substances that can create additional symptoms hours after the original exposure.

The first reaction is called the early reaction. The symptoms occurring hours after the initial exposure make up the late-phase reaction.

For example, an individual who is sensitive to cats will develop an immediate allergic reaction when exposed to a cat. This initial acute attack may continue as long as the individual is exposed. Once the person leaves the environment, the symptoms subside. Later, the release of eosinophils may bring on another wave of the symptoms.

What are the causes and risks of the condition?
The main cause of nasal allergies is an interaction between cells lining the nose and allergens. Common allergens include pollens, dust, dust mites, molds, and animal dander.

What are the treatments for the condition?
The key to allergy treatment is avoiding the allergen. This may be possible for people with pet allergies. It is less practical for those who are sensitive to pollens and molds.

Oral antihistamines are used for short-term allergic disease. Common antihistamines include diphenhydramine, loratadine, and fexofenadine. They are very effective in controlling symptoms such as sneezing and nasal discharge.

Antihistamines generally don't reduce nasal stuffiness. It is common to add a decongestant, such as pseudoephedrine, to an antihistamine. For severe, acute flare-ups, oral steroids, such as prednisone, are used. Steroids block the allergic response.

Nasal steroid sprays, such as beclomethasone and mometasone, are used for prolonged allergies. These agents have been around for about 20 years, and very safe. They control acute symptoms more effectively than antihistamines. Nasal steroids also block the late-phase reaction.

Air filters and frequent vacuuming are helpful. Salt water nasal sprays and mucus thinners, such as guaifenesin, can thin nasal secretions.

Allergy shots can be used in people who have chronic or prolonged periods of allergic disease. The shots desensitize the person to the trigger. They may be given to individuals who are having complications, such as asthma or chronic sinusitis.

What are the side effects of the treatments?



Many over-the-counter antihistamines cause drowsiness and decreased mental alertness. These side effects are less common with newer prescription antihistamines. These include loratadine and certirizine.

Decongestants, such as pseudoephedrine, can cause elevation of blood pressure, fast heart rate, and difficulty sleeping.

Nasal steroids may cause nosebleeds and nasal crusts.

There are a few acute side effects from oral steroids, such as increased appetite, irritability, sleeplessness, weight gain, and stomach irritation. Chronic steroid usage can cause bone thinning, predisposition to infection, diabetes, and cataracts.

Allergy shots may cause a severe allergic reaction or anaphylaxis. They may also bring on an asthma attack.

What happens after treatment for the condition?
With successful treatment of allergies, symptoms should improve.

How is the condition monitored?
Any new or worsening symptoms should be reported to the healthcare provider.