Allergen immunotherapy involves injecting increasing amounts of a diluted allergen into a patient over several months.
Rather than treating the symptoms of allergies, immunotherapy treats the immune system, which is responsible for an allergic reaction. An allergic reaction occurs when the body is exposed to an antigen (foreign substance like pollen, dust mites, mold and pet dander) that is mistakenly identified as a harmful invader. The white blood cells produce an antibody (immunoglobulin E) to the antigen. This process is called sensitization.
Once the body is sensitized, the immune cells will release chemical mediators like histamine when the antigen enters the body. These mediators cause inflammation, as well as allergy symptoms, such as sneezing, runny nose, watery eyes and hives.
Allergy shots desensitize the patient's immune system so it will not react to the antigen. After therapy, the white blood cells produce less immunoglobulin E when the antigen enters the body. The lower amounts of immunoglobulin E mean that a patient's body is not as sensitive to the antigen and allergy symptoms are reduced.
According to the American Academy of Allergy Asthma & Immunology, immunotherapy is only recommended for patients who have allergic asthma, allergic rhinitis (hay fever, an allergic reaction that causes inflammation of the nose), conjunctivitis (pinkeye) and stinging insect allergies. Immunotherapy is not recommended for patients who have food allergies. There is conflicting scientific evidence of the use of immunotherapy for the treatment of atopic dermatitis.
Immunotherapy does not cure allergies, but it may help reduce the body's sensitivity to certain substances. During therapy, some patients may not experience any allergy symptoms. Immunotherapy has shown to prevent the development of new allergies and, in children, it can prevent the progression of allergic rhinitis to asthma. However, the effectiveness of immunotherapy depends on how severe the patient's allergies are, as well as how many substances the patient is allergic to.
WHO SHOULD RECEIVE IMMUNOTHERAPY
According to the American Academy of Allergy Asthma & Immunology, immunotherapy is only recommended for patients who have allergic asthma, allergic rhinitis (hay fever, allergic reaction that causes inflammation of the nose), conjunctivitis (pinkeye) and stinging insect allergies. Immunotherapy is not recommended for patients who have food allergies. There is conflicting scientific evidence of the use of immunotherapy for the treatment of atopic dermatitis.
Once a patient is diagnosed with one of the conditions that are frequently treated with immunotherapy, the healthcare provider assesses the patient to determine the best treatment option. The physician will evaluate the duration and severity of allergy symptoms, how well medications and/or environmental controls manage allergy symptoms, as well as the patient's ability to commit to long-term treatment.
Children who are five years old and older can receive immunotherapy in the United States. Recent studies have indicated that immunotherapy may prevent the development of new allergies in children, and they may also prevent the development of asthma in patients who are diagnosed with rhinitis.
There is no upper age limit for patients who receive immunotherapy. However, since there is a slight chance of severe allergic reactions to immunotherapy, healthcare providers should consider other medical conditions (like heart disease) that may make immunotherapy riskier.
Before receiving immunotherapy, patients should tell their healthcare providers if they are taking any drugs (prescription or over-the-counter), herb or supplements.
Patients should not engage in any vigorous physical activity two hours before and after treatment. Exercise may increase the blood flow to the tissues and promote faster release of antigens from the allergy shot into the bloodstream.
Patients should consult their healthcare providers about the safety of immunotherapy if they are pregnant or trying to become pregnant. If a pregnant woman experiences anaphylaxis in response to immunotherapy, the fetus may be harmed.
HOW IT IS PERFORMED
Allergen immunotherapy works like a vaccine. A diluted extract of the allergen that the patient is allergic to is injected into the patient. The patient responds to the treatment by developing an immunity or tolerance to the allergen. As a result of these immune changes, immunotherapy can lead to decreased, minimal or no allergy symptoms when the patient is exposed to the particular allergen again.
There are two phases of immunotherapy - the build-up phase and the maintenance phase. During the build-up phase, allergy shots are injected into the upper arm once or twice a week for several months (typically three to six months). The dose is gradually increased until the maintenance dose is reached.
The maintenance phase begins once the effective therapeutic dose is reached. This dose is different for each patient because it depends on the patient's level of allergen sensitivity and their response to immunotherapy during the build-up phase. Once the maintenance dose is reached, the patient will continue therapy every two to four weeks for two to five years or more.
RESPONSE TO IMMUNOTHERAPY
Patients may begin to experience reduced allergy symptoms during the build-up phase of treatment. However, other patients may not experience reduced symptoms for as long as 12 months on the maintenance dose. Allergic responses may improve progressively with immunotherapy. The effectiveness of immunotherapy seems to be related to both the length of treatment and the dose of the allergen.
Some patients may not respond to treatment at all. This may occur if the injections contain inadequate doses of the allergen, if additional allergens were not identified during the allergy evaluation, if the patient is exposed to high levels of non-allergic triggers (like tobacco smoke) or if there are high levels of the allergen in the home or work environment that cannot be avoided.
There are two types of side effects associated with immunotherapy - local and systemic (occurring in many areas throughout the body).
Local reactions are relatively common and may include redness and swelling at the injection site. This can occur immediately after treatment or several hours later.
Systemic reactions are much less common, and they are usually mild and responsive to medications. Symptoms typically develop within 30 minutes of treatment and require immediate treatment. Symptoms may include increased allergy symptoms like nasal congestion, hives or sneezing. A rare, but life-threatening reaction called anaphylaxis has also been reported. Symptoms of anaphylaxis can vary from mild to severe The most dangerous symptoms are low blood pressure, breathing difficulties, shock and loss of consciousness, all of which can be fatal. Anaphylaxis is an emergency condition that requires immediate medical attention. Epinephrine is a medication used to treat severe allergic reactions such as anaphylaxis. Administering the epinephrine as soon as possible improves the patient's chance of survival and a quick recovery.
In addition to traditional allergy shots, several new immunotherapy techniques have been suggested. These therapies are currently undergoing trials to determine their effectiveness for the treatment of allergies.
Rush immunotherapy: Rush immunotherapy involves a more rapid build-up phase. The patient receives increasing doses of the allergen every few hours rather than every few days. However, patients who receive rush immunotherapy have an increased risk of developing systemic side effects such as anaphylaxis. Therefore, patients undergoing this therapy should receive treatment in a hospital, under close medical supervision.
Oral immunotherapy: Oral immunotherapy works similarly to traditional immunotherapy, except the allergen extract is administered as an oral droplet. Doses and treatment duration are generally the same as traditional immunotherapy. Oral immunotherapy has shown to be beneficial in some patients. However, this therapy is not approved for use in the United States.
Intranasal immunotherapy: Several controlled, well-designed studies suggest that intranasal (inside the nose) administration of birch tree, grass and dust mite allergen extracts may effectively reduce nasal symptoms of rhinitis, such as nasal congestion and sneezing. The main side effect associated with intranasal immunotherapy is irritation of the tissues inside the nose. However, this therapy may not produce the same long-lasting effects that have been associated with traditional immunotherapy. Intranasal immunotherapy is not currently available for use in the United States.
Bromelain: It is proposed that bromelain may be a useful addition to other therapies that are used to treat sinusitis (such as antibiotics). Bromelain is thought to reduce inflammation and swelling caused by allergens. Studies report mixed results, although overall bromelain appears to be beneficial for reducing swelling and improving breathing. Better studies are needed before a strong recommendation can be made.
Avoid if allergic to bromelain, pineapple, honeybee, venom, latex, birth pollen, carrots, celery, fennel, cypress pollen, grass pollen, papain, rye flour, wheat flour or other members of the Bromeliaceae family. Use cautiously with history of bleeding disorders, stomach ulcers, heart disease, liver disease or kidney disease. Use cautiously before dental or surgical procedures or while driving or operating machinery. Avoid if pregnant or breastfeeding.
Butterbur: Comparisons of butterbur to prescription drugs, such as fexofenadine (Allegra©) and cetirizine (Zyrtec©), have reported similar efficacy. These results suggest benefits of butterbur for prevention of allergic rhinitis. Additional research is warranted before a strong recommendation can be made.
Avoid if allergic or hypersensitive to Petasites hybridus or other plants from the Asteraceae/Compositae family (like ragweed, marigolds, daisies and chrysanthemums). Raw, unprocessed butterbur plant should not be eaten due to the risk of liver or kidney, damage or cancer. Avoid if pregnant or breastfeeding.
Nasal irrigation: There is good evidence from randomized controlled and equivalence trials, and case series, to recommend the use of nasal irrigation in the treatment of allergic rhinitis. One study demonstrated reflexology massage as being equally effective. However the advantage of irrigation (i.e. inexpensive, performed at home, minimal side effects) makes the technique beneficial. Methodological and statistical reporting are lacking in some of these trials. A well-conducted randomized controlled trial fully reporting data would make the case for allergic rhinitis stronger.
There is good evidence from randomized controlled trials, case series, and equivalence trials to recommend the use of nasal irrigation in the treatment of chronic sinusitis. A large, randomized, double-blinded study would lend strong support to the usage of nasal irrigation for the treatment of chronic sinusitis.
There are three forms of nasal irrigation therapies. Saline lavage uses a warm liquid solution, while large-particle nebulized aerosol therapy uses aerosolized saline solution. A humidified warm air lavage (hyperthermia) is also used. Occasionally, antibiotics are added to the solution. Nasal saline irrigation is still the main treatment for acute rhinitis in infants since excessive usage of vasoconstrictor nose drops is not recommended in early childhood.
Acupuncture: More studies are needed of stronger design to determine whether or not acupuncture can effectively treat chronic sinusitis.
Acupuncture plus point-injection has been found beneficial for hives, although more research is needed to confirm these findings.
Cat's claw: There is insufficient evidence to recommend cat's claw for allergic respiratory diseases at this time.
Choline: Oral tricholine citrate (TRI) effectively relieved allergic rhinitis symptoms of in one study. Further research is needed before a recommendation can be made.
Ephedra: Preliminary study suggests that ephedrine nasal spray, which is made from a chemical in ephedra, may help treat symptoms of nasal allergies. Additional research is needed before a recommendation can be made.
A randomized, controlled trial has shown promising results of a 1% ephedrine saline nasal wash in the treatment of allergic rhinitis. Results from further randomized, controlled trials are warranted before recommending for or against the use of ephedrine in the treatment of allergic rhinitis. Although effects in this study reportedly lasted for 2-4 weeks, there is a theoretical a concern that tolerance might develop. Notably, saline nasal washes alone have been demonstrated as effective. Further research is warranted in this area, with a long-term comparison to saline monotherapy and nasally inhaled corticosteroids.
Eucalyptus oil: Although commonly used in non-prescription products, there is inconclusive scientific study of eucalyptus oil or eucalyptol. Better research is necessary before a recommendation can be made.
Honey: Currently, there is insufficient human evidence to recommend honey for the treatment of rhinoconjunctivitis. One poor quality trial reported no benefit of the use of honey for the treatment of rhinoconjunctivitis.
Hypnotherapy/hypnosis: Preliminary research has provided inconclusive evidence on the use of hypnotherapy for the treatment of hay fever. More well-designed clinical trials are needed before a firm conclusion can be made.
Lactobacillus acidophilus: A small study was conducted to evaluate the effects of Lactobacillus acidophilus strain L-92 (L-92) on the symptoms of Japanese cedar-pollen allergy with positive results. Further research is needed before a firm conclusion can be made.
Perilla: Preliminary evidence suggests some benefit of perilla extract for seasonal allergies. Further clinical trials are required before recommendations can be made.
Probiotics: Probiotics show promise for reducing or preventing atopic dermatitis (eczema) in children. Infants benefit when their mothers take probiotics during pregnancy and breastfeeding. Direct supplementation for infants may reduce incidence of atopic eczema by as much as half. It may also reduce cow's milk allergy and other allergic reactions during weaning. Probiotics may stabilize the intestinal barrier function and decrease gastrointestinal symptoms in children with atopic dermatitis. Children do differ, however, in their responsiveness to specific probiotics.
Sorrel: There is no reliable human evidence evaluating sorrel monotherapy as a treatment for sinusitis. However, it is an ingredient contained in combination formulas marketed for sinusitis, including Sinupret© (a combination product including cowslip flower, European elderflower, gentian root and verbena, which is available in Europe) and Quanterra© Sinus Defense (the U.S. equivalent of Sinupret©, not manufactured since 2000). Although there is promising early evidence for this formula in patients with sinusitis, better quality research is necessary before a firm conclusion can be drawn.
Stinging nettle: For many years, a freeze-dried preparation of Urtica dioica has been prescribed by physicians and sold over-the-counter for the treatment of allergic rhinitis. Clinical trials demonstrating statistical significance over placebo, and/or equivalence with other available treatments, are needed to support the use of nettle in the treatment of allergic rhinitis.
Vitamin E: Although vitamin E is commonly thought to help reduce the nasal symptoms of allergies, it may not be effective. Current evidence is limited, however, and more studies are needed before a firm conclusion can be drawn.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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