Treating Allergy With Allergen Immunotherapy
An allergy is an exaggerated defense reaction of the immune system to some normally harmless environmental substances. These substances are called allergens. The aim of allergy treatment is not only to reduce symptoms but also to prevent disease progression and subsequent organ damage.
Allergen immunotherapy is a form of long-term treatment that decreases symptoms for many people with allergic rhinitis, allergic asthma, conjunctivitis (eye allergy) or stinging insect allergy. They decrease sensitivity to allergens and often leads to lasting relief of allergy symptoms even after treatment is stopped. This makes it a cost-effective, beneficial treatment approach for many people.
Let’s answer some simple questions before we dig deep:
Q What is the goal of immunotherapy?
A To treat the cause of allergy.
Q What is the basis of this approach?
A To get the immune system accustomed to the allergens in the environment.
Q What is the Impact of such therapy?
A Alleviate discomfort. Prevent disease progression and emergence of new allergies.
ALLERGEN IMMUNOTHERAPY - TREAT THE CAUSE OF ALLERGY
Allergen immunotherapy (AIT) is the only form of treatment that counters the cause of allergy and may thus have a lasting effect on one’s state of health. Discomfort is alleviated and the quality of life improved. It also prevents progression of the allergic disease. Thus allergen immunotherapy may prevent the march of allergy from the upper airways (allergic rhinitis) to the lower airways (allergic asthma) as well as the development of new allergies. It is therefore best suited for young patients with allergy (≥ 5 years) and for patients with early allergic rhinitis or allergic asthma. Likewise, allergen immunotherapy may significantly contribute to symptomatic improvement even in patients with a prolonged illness.
COURSE AND DURATION OF ALLERGEN IMMUNOTHERAPY
Once you have opted for allergen immunotherapy, there are two ways to introduce allergy-triggering allergens into your body: either subcutaneous immunotherapy (SCIT) as an injection into subcutaneous tissue or via the oral mucosa (sublingual immunotherapy, SLIT). Allergen immunotherapy is generally given for three years. Symptoms may regress even in the first year after starting treatment and may continue improving noticeably in the following years.
Subcutaneous allergen immunotherapy (SCIT) is administered as a subcutaneous injection. A slow and gradual increase in the amount allows the body to become accustomed to the allergens and to tolerate them. Treatment itself may be divided into two phases:
During initiation therapy or build up phase, an increasing amount of allergen is injected into the upper arm until the maximum dose for the individual patient (maintenance dose) is reached. The intervals between injections in this phase is usually one week. The length of this phase generally ranges from three to six months.
After reaching the maximum dose, intervals between injections in the so-called maintenance therapy may be extended to 4 or 8 weeks. Your Allergy Specialist will decide what range is best for you.
You may notice a decrease in symptoms during the build-up phase, but it may take as long as 12 months on the maintenance dose to notice an improvement. If immunotherapy is successful, maintenance treatment is generally continued for three to five years. Any decision to stop the therapy should be discussed with your Allergy Specialist.
WHAT IS THE THE RIGHT TIME TO BEGIN?
For seasonal complaints, such as due to pollen, subcutaneous immunotherapy (SCIT) is usually started at the end of the season during the symptom-free period. Therapy may be commenced at any time in patients with all-year-round symptoms, as happens with mite allergy.
WHO CAN BENEFIT FROM ALLERGY SHOTS?
Both children and adults can receive allergen immunotherapy, although it is not typically recommended for children under age five. This is because of the difficulties younger children may have in cooperating with the program and in articulating any adverse symptoms they may be experiencing. When considering allergy shots for an older adult, medical conditions such as cardiac disease should be taken into consideration and discussed with your Allergy Specialist first.
You and your allergist should decide regarding immunotherapy on:
- Length of allergy and severity of the symptoms
- How well environmental control measures are helping your allergy symptoms
- Your desire to avoid long-term medication use
- Time available for treatment (immunotherapy requires a significant commitment)
- Cost, which may vary with the allergen used for therapy
Allergen Immunotherapy are not used to treat food allergies. The best option for people with food allergies is to strictly avoid that food.
HOW DO ALLERGEN IMMUNOTHERAPY WORK?
They work like a vaccine. Your body responds to injected or ingested amounts of a particular allergen, given in gradually increasing doses, by developing immunity or tolerance to the allergen.
HOW EFFECTIVE ARE ALLERGEN IMMUNOTHERAPY?
They have shown to decrease symptoms of many allergies. It can prevent the development of new allergies, and in children it can prevent the progression of allergic disease from allergic rhinitis to asthma. The effectiveness of allergy shots appears to be related to the length of the treatment program as well as the dose of the allergen. Some people experience lasting relief from allergy symptoms, while others may relapse after discontinuing the therapy. If you have not seen improvement after a year of maintenance therapy, your Allergy Specialist will work with you to discuss treatment options.
Failure to respond to the therapy may be due to several factors:
- Inadequate dose of allergen in the allergy vaccine
- Missing allergens not identified during the allergy evaluation
- High levels of allergen in the environment
- Significant exposure to non-allergic triggers, such as tobacco smoke
WHERE ALLERGEN IMMUNOTHERAPY SHOULD BE TAKEN?
This type of treatment should be supervised by a specialized physician in a facility equipped with proper staff and equipment to identify and treat adverse reactions to allergy injections. Ideally, immunotherapy should be given by an Allergy Specialist. If this is not possible, your allergist should provide the supervising physician with detailed instructions about your allergen immunotherapy.
ARE THERE RISKS?
A typical reaction is redness and swelling at the injection site. This can happen immediately or several hours after the treatment. In some instances, symptoms can include increased allergy symptoms such as sneezing, nasal congestion or hives.
Serious reactions to allergen immunotherapy are rare. When they do occur, they require immediate medical attention. Symptoms of an anaphylactic reaction can include swelling in the throat, wheezing or tightness in the chest, nausea and dizziness. Most serious reactions develop within 30 minutes of the allergy injections. This is why it is recommended you wait in your doctor's clinic or hospital for at least 30 minutes after you receive allergy immunotherapy.
POINTS TO CONSIDER:
- Discuss your medical history with your allergist before beginning therapy to determine whether the allergen immunotherapy is suitable for you.
- Be sure to keep your appointments to ensure success of therapy.
- A variety of symptoms typical of allergy may occur after the injection. Therefore, you must wait at least 30 minutes in the doctor’s clinic or hospital after each injection. Inform the medical personnel about any discomfort you may have.
- Refrain from physical exertion and alcohol after the injection, as these factors may amplify a possible reaction to the allergen.
- Redness, itching and swelling may occur at the injection site even hours after the injection.
- Inform your doctor how well you tolerated each dose. Also about the medical treatments and newly occurred illnesses.
If you have any allergy related issues feel free to contact Allergy Specialist in Bangalore - Dr. Puneeth KN for a consultation.
About the Author
Dr Puneet. K. Nagendra
MBBS, DTCD, DNB (Pulmonary Medicine)
Presently I render my clinical services as an Allergist & Pulmonologist in Bengaluru Allergy Centr, PD Hinduja Sindhi Hospital, Excelcare Hospital and Mahapranajeeva - Speciality Centre for Respiratory diseases at Bengaluru.
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