Allergic rhinitis is an inflammatory condition of the nose and nasal sinuses that occur when a person is exposed to something they are allergic to. Allergens are substances that cause allergic reactions in some people but cause no symptoms in others who are not allergic. Allergens can be found indoors and outdoors. When a person is allergic to outdoor allergens it is often referred to as “Hay Fever” and occurs seasonally. Persons who are allergic to indoor allergens usually suffer throughout the year.
Allergens cause the immune system to recognize the allergen as an “invader” and release substances known as IgEs and chemicals such as histamine in order to “attack” the “invader”. This immune response is an allergic reaction and is responsible for causing the symptoms associated with allergic rhinitis. Allergic rhinitis can be diagnosed at any age but is the most common chronic condition diagnosed in childhood.
Allergic Rhinitis is caused by airborne allergens both inside and outside the home. Common allergens that cause Allergic Rhinitis can include:
- Ragweed (autumn)
- Tree pollen (springtime)
- Grass pollen (spring and summertime)
- Fungus or mould (indoor and outdoor)
- Dust mites in the house
- Animal dander
- Cockroach droppings
- Air pollution
Risk factors increase your chances of developing a disease or condition. Risk factors for Allergic Rhinitis include:
- Genetic History: There is an established risk factor between allergic rhinitis and family history of allergy. A child has a 50% likelihood of developing allergic rhinitis if one parent has it and a 75% chance if both parents have allergic rhinitis.
- Medical Conditions: Patients with a history of food allergies, asthma or eczema are at increased risk of developing allergic rhinitis.
- Environment: Allergic Rhinitis is more prevalent in developed countries and the prevalence is increasing with urbanization. Some possible factors are increased exposure to pollution and irritants such as second hand smoke. Changes in our diets and increased stress have also been discussed as possible contributors to the increase in cases.
Allergic rhinitis can predispose a person to develop:
- Middle ear infections (Otitis Media)
- Sleep disorders
- Upper respiratory tract infections
Signs and symptoms
Symptoms of allergic rhinitis are similar to cold symptoms. It is important to understand however that allergic rhinitis is not an infection and therefore cannot be passed from person to person like the common cold. Symptoms of allergic rhinitis can occur seasonally (intermittent allergic rhinitis) or throughout the year (persistent allergic rhinitis).
Symptoms of allergic rhinitis can include any or all of the following:
- Runny nose
- Stuffy or blocked nose
- Post nasal drip
- Itching of the nose
- Excessive sneezing
- Watering and itching of eyes
- Swollen eyes
- Itching of the throat
Allergic rhinitis is diagnosed by a combination of patient history, examination of nasal passages (rhinoscopy) and lab tests. The following tests may be performed by your physician to help with diagnosing your condition:
- Blood Tests: Blood tests are taken to detect the presence of increased eosinophil cells in blood. Eosinophils are a type of white blood cells which increase in number in patients with allergies. Blood tests for allergens include radio allegro sorbent test (RAST) or enzyme-linked immunosorbent assay (ELISA).
- Nasal smear: A nasal smear may be obtained to examine for eosinophil cells which are usually increased in patients with allergic rhinitis.
- Skin prick test: In this test, a standardized allergen extract is introduced into the skin of the forearm with a tiny needle and observed for reaction after 15 minutes. Reactions greater than 3 mm are regarded positive. Patients should not take any antihistamines 2 days prior to the skin prick test. Skin prick tests are simple, cheap and safe. Systemic reactions are very rare and multiple allergens can be tested in the same sitting.
- Nasal allergen challenge: An allergen is introduced into the nose and any reaction is measured and compared to a placebo. This is the gold standard for allergy diagnosis. Nasal challenge test is time consuming, difficult and requires extensive laboratory facilities.
Conservative treatment measures to treat Allergic Rhinitis can include the following:
- Avoidance of allergenIdentifying the allergens and avoiding them is the first method of treatment. Major indoor allergens include house dust mites, domestic pets, cockroaches and mould spores. Some measures that are helpful for avoiding allergens include using allergen proof covers for mattresses and pillows. Use hot water when washing your bedding. Remove objects that accumulate dust, treat carpets with anti-allergen products, and avoid keeping pets in the home. If pets are in the home they should be washed regularly and kept out of bedrooms. Seasonal rhinitis results from exposure to outdoor pollens. Try to avoid grassy, open spaces when outdoors. Use air conditioning and change your filters frequently instead of opening windows.
- AntihistaminesAntihistamines help prevent symptoms caused by allergies, colds and influenza by blocking histamine, one of the chemicals released in an allergic reaction. The first type of antihistamines developed caused excessive drowsiness, but there are newer antihistamines that have been developed that do not make you sleepy. Antihistamines can interact with other drugs or cause adverse side effects. Talk with your doctor about the best antihistamine for your particular situation.
- Topical steroidsTopical steroid are the most effective treatment for allergic rhinitis. Regular use is necessary as the onset of action is slow and maximum effect occurs after several days. Nasal steroids reduce nasal inflammation, eye symptoms and improve the sense of smell. They also can reduce the risk of asthma exacerbations. Side effects can include nasal bleeding and minor irritation.
- Mast cell stabilizersThese are medications that prevent the release of histamine, one of the mediators responsible for allergic symptoms. These are usually in the form of nasal sprays to treat allergic rhinitis.
- DecongestantsDecongestant nasal drops or sprays reduce nasal obstruction, but prolonged use can cause a condition called Rhinitis Medicamentosa where there is excessive nasal obstruction and loss of response to the drug. Systemic decongestants taken by mouth also can reduce nasal obstruction. Talk to your doctor as to the best choice for your situation.
- Systemic corticosteroidsFor very severe symptoms, oral steroid tablets may be ordered by your physician. Regular use is associated with significant systemic side effects.
- ImmunotherapyAllergen immunotherapy involves repeatedly exposing the patient to small amounts of the allergen that is causing their symptoms. This repeated exposure eventually creates a tolerance to the allergen. This reduces clinical symptoms and also the requirements for medication during subsequent natural allergen exposure. It is indicated for patients with severe allergic rhinitis who fail to respond adequately to drug therapy. Immunotherapy offers the potential for long-term disease modification and prophylaxis. Local reactions are minimal. Systemic reactions occur in 10% of people, which include symptoms like mild asthma and itching. Rarely severe reactions like anaphylaxis and generalized body itching occur. In view of the systemic side effects, it is performed only in specialist centres.
- SurgeryThere is no surgery that can be performed to cure Allergic Rhinitis. There are occasions, however, where your physician may recommend surgery. If a patient has a deviated nasal septum or nasal polyps that prevent the proper administration of medications to treat their rhinitis, surgery to correct the deformity or to remove the polyps may be recommended.
Occasionally, the insertion of ear tubes may be recommended in children with allergic rhinitis.