Year-round (perennial) allergies result from exposure to airborne substances (such as house dust) that are present throughout the year.
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 mites, 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.
Usually, perennial allergies cause nasal symptoms (allergic rhinitis) but not eye symptoms (allergic conjunctivitis). However, allergic conjunctivitis can result when certain substances are purposely or inadvertently placed in the eyes. These substances include drugs used to treat eye disorders, cosmetics such as eyeliner and face powder, and hair dye. The cleaning solutions for contact lenses can cause an allergic reaction. Perennial rhinitis is often caused by something other than an allergy, such as aspirin or another nonsteroidal anti-inflammatory drug (NSAID).
Symptoms and Diagnosis
The most obvious symptom 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.
Many people who have a perennial allergy also have asthma, possibly caused by the same allergens that contribute to allergic rhinitis and allergic conjunctivitis.
Diagnosis is based on symptoms plus the circumstances in which they occur—that is, in response to certain activities, such as petting a cat.
Avoiding the allergen, if possible, is recommended, thus preventing the development of symptoms.
If people are allergic to house dust, some changes in the environment can prevent or lessen symptoms:
If a person is allergic to animal dander, the family pet may be limited to certain rooms of the house or, if possible, kept out of the house. Washing the pet weekly can also help.
Drug treatment is similar to that for seasonal allergies (see Treatment). It includes corticosteroid nasal sprays, antihistamines, and decongestant nasal sprays.
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, regularly flushing out the sinuses with a warm water and salt (saline) solution may be helpful. This technique is called sinus irrigation.
Last full review/revision August 2012 by Peter J. Delves, PhD