What is allergic rhinitis?
Allergic rhinitis (“AR”) is an immune-mediated disease (immunoglobulin E) that occurs after exposure to outdoor and/or indoor allergens (substances that produce an allergic reaction). Such allergens include dust mites, animal dander, insects, dust, molds, and pollens. When you breath in these allergens, they trigger an allergic response. The body releases certain chemicals, including histamine, which causes allergy symptoms such as itching, swelling, and mucus production.
Allergic rhinitis due to plant pollen is commonly referred to as “hay fever.” Depending upon the person and the region, the causes of hay fever varies. Common causes of hay fever include trees (especially in the spring), grasses (late spring and summer) and ragweed (late summer and early autumn). The likelihood of hay fever symptoms developing increases when there is more pollen in the air. On hot, dry, and windy days, there is more airborne pollen than on cool, rainy days.
What are the symptoms of allergic rhinitis?
Symptoms of AR can occur shortly after contact (acute symptoms) with the allergen or develop later on (chronic symptoms). Acute symptoms may include:
- Itching (“pruritis”), especially the nose, eyes, throat, mouth or skin
- Runny nose (“rhinorrhea”)
- Altered sense of smell
- Tearing eyes
Symptoms that may develop later include:
- Chronic cough
- Nasal congestion and loss of sense of smell
- Sore throat
- Clogged ears and/or hearing loss
- Puffiness and/or dark circles under the eyes
- Fatigue and irritability
- Memory problems and slowed thinking
How is allergic rhinitis diagnosed?
Your physician will take a complete history and then perform a physical examination. Your history of symptoms is important in diagnosing allergic rhinitis. In addition to symptoms, your doctor will elicit information about exposure to pets or other allergens, environmental exposures, the relationship of symptoms to time of day or season, and presence of other allergic conditions. Some diseases can be associated with AR, including asthma and eczema. Your family history of allergies and allergic disease is also important because these are commonly passed from parent (especially mother) to child.
Allergy testing may reveal the specific substances that trigger your symptoms. Skin testing is the most common method of allergy testing. Blood testing may includes Complete Blood Count (CBC), with eosinophil white blood cell count, and Immunoglobulin E level.
How is AR treated?
Optimal treatment includes allergen avoidance, control of symptoms, immune therapy, and asthma evaluation, when appropriate. The best treatment for AR is to avoid exposure to the allergens causing your symptoms. Although it might not be possible to completely avoid all of your triggers, you can take steps to reduce exposure.
- Intranasal corticosteroids: For mild to moderate AR, intranasal corticosteroid sprays are the most effective treatment available. According to several studies, nasal corticosteroids are more effective than oral and intranasal antihistamines for allergic rhinitis. These sprays work best when used nonstop, but they can also be helpful when used for shorter periods of time. These sprays begin working in about 30 minutes but might require 2-4 weeks to reach maximal effect. There are many brands available in the US. They are considered safe for children and adults. There is no evidence that one corticosteroid is superior to another. Adverse side effects may include nosebleeds, stinging or burning of the throat, hoarseness, and dryness or sores of the mouth and nasal passages. The various intranasal corticosteroids appear to be comparably effective to one another, but only budesonide (Rhinocort Aqua) has a category B safety rating and has approval by the FDA for use during pregnancy.
For patients with moderate to severe allergic rhinitis, second-line treatments include antihistamines, decongestants, intranasal cromolyn, leukotriene receptor antagonists, intranasal anticholinergics, allergy shots, and non-pharmacological interventions such as nasal irrigation. Combination therapy has not been found to be superior to monotherapy with intranasal corticosteroids.
- Antihistamines: Most antihistamines can be taken by mouth, and many preparations are available “over-the-counter.” You should check with your doctor before taking these on a long-term basis, especially for children. Although second-generation antihistamines are effective for relieving some nose and eye symptoms, they are mostly ineffective for nasal congestion. Except for cetirizine (Zyrtec), second-generation antihistamines are less likely to cause sedation or impair performance. Azelastine (Astelin) and olopatadine (Patanase) are antihistamine nasal sprays approved by the FDA for treatment of allergic rhinitis but have limited use because of adverse effects (including bitter aftertaste, headache, nasal irritation, epistaxis, and sedation), higher cost, and decreased efficacy compared to intranasal corticosteroids. Antihistamines work well for treating many allergy symptoms, especially when they do not happen very often or last very long.
- Decongestants: These may be helpful in reducing symptoms such as nasal congestion but should not be used for more than 3-4 days. These can be taken orally or as a spray. Adverse effects include sleeplessness, anxiety, high blood pressure, and rebound nasal congestion (worsening of symptoms after withdrawal of medicine).
- Intranasal cromolyn: Intranasal cromolyn is safe for general use for allergic rhinitis, but it is not considered first-line treatment because of its lower efficacy for symptom relief and its inconvenient dosing schedule (3-4 times daily).
- Leukotriene receptor antagonists: Oral montelukast (Singulair) is FDA approved for allergic rhinitis but has been found to be less effective than intranasal corticosteroids and antihistamines and should not be used as first- or second-line therapy.
- Intranasal anticholinergics: Ipratropium (Atrovent) nasal spray is useful for excessive rhinorrhea (runny nose), but has to be administered 2 to 3 times daily.
- Allergy shots: Allergy shots (“immunotherapy”) are occasionally recommended for patients with unsatisfactory response to usual therapy and if the allergen cannot be avoided. Allergen-specific vaccines have been developed with use of recombinant DNA technology. This treatment consists of regular injections of the allergen, given in increasing doses. Anaphylaxis (a life-threatening allergic reaction) is the most severe adverse event potentially associated with immunotherapy. Allergy shots may significantly relieve symptoms, while reducing skin sensitivity and use of other medications.
- Non-pharmacological: There is insufficient evidence for the efficacy of non-pharmacological therapies such as acupuncture, probiotics, and herbal supplements; therefore, such alternative treatments are not medically recommended at this time. Despite the high prevalence of dust mite allergies, mite-proof impermeable mattress and pillow covers have not been shown to be effective against allergic rhinitis in any studies. Be careful when using over-the-counter saline nasal sprays that contain benzalkonium chloride, as these may actually worsen symptoms and cause infection. For mild allergic rhinitis, a saline nasal wash can be helpful for removing mucus from the nose. The use of air filtration systems have no documented efficacy in preventing allergic rhinitis
What is the prognosis?
Generally the symptoms of AR can be treated successfully. More severe cases might require allergy shots. Some patients, especially children, may become less sensitive to the allergen. However, as a general rule, once a substance causes allergies for an individual, it can continue to affect the person over the long term.