Year-round (perennial) allergies result from indoor exposure to airborne substances (such as house dust) that are present throughout the year.
The nose is congested, itchy, and sometimes runny, and the mouth and throat are itchy.
The symptoms and activities that trigger the allergy usually suggest the diagnosis.
Avoiding the allergen is best, but drugs, such as antihistamines, can help relieve symptoms.
(See also Overview of Allergic Reactions.)
Perennial allergies may occur at any time of year—unrelated to the season—or may last year-round. Perennial allergies are often a reaction to house dust. House dust may contain mold and fungal spores, fibers of fabric, animal dander, dust mite droppings, and bits of insects. Substances in and on cockroaches are often the cause of allergic symptoms. These substances are present in houses year-round but may cause more severe symptoms during the cold months when more time is spent indoors. (Substances that trigger an allergic reaction are called allergens.)
Usually, perennial allergies cause nasal symptoms (allergic rhinitis) but not eye symptoms (allergic conjunctivitis). However, allergic conjunctivitis can result when allergens are inadvertently rubbed into the eyes. The cleaning solutions for contact lenses can also sometimes cause an allergic reaction.
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Symptoms of Year-Round Allergies
The most obvious symptom of perennial allergies is a chronically stuffy nose. The nose runs, producing a clear watery discharge. The nose, roof of the mouth, and back of the throat may itch. Itching may start gradually or abruptly. Sneezing is common.
The eustachian tube, which connects the middle ear and the back of the nose, may become swollen. As a result, hearing can be impaired, especially in children. Children may also develop chronic ear infections. Some people have recurring sinus infections (chronic sinusitis) and growths inside the nose (nasal polyps).
When affected, the eyes water and itch. The whites of the eyes may become red, and the eyelids may become red and swollen. The skin under the eyes can become dark (allergic shiner).
Many people who have a perennial allergy also have asthma, possibly caused by the same allergy triggers (allergens) that contribute to allergic rhinitis and allergic conjunctivitis.
Diagnosis of Year-Round Allergies
A doctor's evaluation
Diagnosis of perennial allergies is based on symptoms plus the circumstances in which they occur—that is, in response to certain activities, such as petting a cat. It can often be diagnosed based on this information alone.
Allergy testing
Tests are needed only if people do not respond to treatment.
In such cases, skin prick tests can help confirm the diagnosis and identify the trigger for symptoms (such as dust mites or cockroaches). For these tests, a drop of each extract is placed on the person’s skin, which is then pricked with a needle through the drop. Doctors then watch to see if there is a wheal and flare reaction (a pale, slightly elevated swelling surrounded by a red area).
An allergen-specific immunoglobulin (IgE) test is done if results of the skin test are unclear or skin testing cannot be done. For this test, a sample of blood is withdrawn and tested.
Prevention of Year-Round Allergies
Avoiding or removing the allergen, if possible, is recommended, thus preventing the development of symptoms and the need to take medication.
If people are allergic to house dust, animal dander, or other indoor allergens, some changes in the environment may prevent or lessen symptoms:
Removing items that collect dust, such as knickknacks, magazines, and books
Removing soft toys
Replacing upholstered furniture and carpets or vacuuming them frequently
Replacing draperies and shades with blinds
Frequently washing bed sheets, pillowcases, and blankets in hot water
Treating homes with heat-steam
Covering mattresses and pillows with finely woven fabrics that cannot be penetrated by dust mites and allergen particles
Using synthetic-fiber pillows
Frequently cleaning the house, including dusting, vacuuming, and wet-mopping
Using air conditioners and dehumidifiers to reduce the high indoor humidity that encourages the breeding of dust mites
Using high-efficiency particulate air (HEPA) vacuums and filters
Limiting pets to certain rooms or keeping them out of the house and washing the pet frequently
Exterminating cockroaches
Treatment of Year-Round Allergies
Corticosteroid nasal sprays
Antihistamines
Decongestants
Sometimes allergen immunotherapy
For nasal polyps, sometimes surgery
Avoiding the allergen is the best way to treat as well as prevent allergies.
Drug treatment of perennial allergies is similar to that for seasonal allergies. It includes corticosteroid nasal sprays, antihistamines, and decongestants.
A corticosteroid nasal spray is usually very effective and is used first. Most of these sprays have few side effects, although they can cause nosebleeds and a sore nose.
An antihistamine,
Many antihistamine-decongestant combinations are available over the counter as a single tablet. However, people with high blood pressure should not take a decongestant unless a doctor recommends it and monitors its use. Also, people who take a monoamine oxidase inhibitor (a type of antidepressant) cannot take a product that combines an antihistamine and a decongestant. Antihistamine-decongestant combination drugs should not be given to young children.
Antihistamines may have side effects, particularly anticholinergic effects. Anticholinergic effects include sleepiness, dry mouth, blurred vision, constipation, difficulty with urination, confusion, and light-headedness.
Decongestants are also available over the counter as nose drops or sprays. They should not be used for more than a few days at a time because using them continually for a week or more may worsen or prolong nasal congestion—called a rebound effect—and may eventually result in chronic congestion.
Side effects tend to be fewer and less severe with nasal sprays than with drugs taken by mouth.
Other drugs are sometimes useful. Cromolyn (a mast cell stabilizer) is available by prescription as a nasal spray and may help relieve a runny nose. To be effective, it must be used regularly.
Regularly flushing out the sinuses with a warm water and salt (saline) solution may help loosen and wash out mucus and hydrate the nasal lining. This technique is called sinus irrigation.
When these treatments are ineffective, a corticosteroid may be taken by mouth or by injection for a short time (usually for fewer than 10 days). If taken by mouth or injection for a long time, corticosteroids can have serious side effects.
Allergen immunotherapy (desensitization)
If other treatments are ineffective, allergen immunotherapy helps some people.
Desensitization is a process that tries to teach the person's immune system not to react to an allergen. The person is given progressively larger doses of the allergen. The first dose is so small that even an allergic person will not react to it. However, the small dose starts to get the person's immune system used to the allergen. Then the dose is gradually increased. Each increase is so small that the immune system still does not react. The dose is increased until the person is not reacting to the same amount of allergen that once caused symptoms.
Immunotherapy is needed in the following situations:
When symptoms are severe
When the allergen cannot be avoided
When the drugs usually used to treat allergic rhinitis or allergic conjunctivitis cannot control symptoms
Immunotherapy for year-round allergies consists of giving gradually increasing doses of allergen placed under the tongue (sublingual) or injected into the skin. Because desensitization occasionally causes dangerous allergic reactions, people remain in the doctor’s office for at least 30 minutes afterward. If they do not have a reaction after first dose, they can take subsequent doses at home.
Allergen immunotherapy for hay fever should be started after the pollen season to prepare for the next season. Immunotherapy has more side effects when started during pollen season because the pollen allergens have already stimulated the immune system. Immunotherapy is most effective when continued year-round.
Surgery
For people with chronic sinusitis and nasal polyps, surgery is sometimes needed to improve sinus drainage and remove infected material or to remove the polyps. Before and after surgery, regular sinus irrigation may be helpful.
