Allergy shots

Allergy shots also called 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. Allergy shots 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. If you want want to start allergy shots, find a board certified allergist/immunologist here (https://allergist.aaaai.org/find).

Allergy shots can treat some types of allergies. Allergy shots or allergen immunotherapy is appropriate for patients with immunoglobulin E (IgE)-mediated allergic diseases such as seasonal allergic rhinitis, perennial rhinitis, allergic asthma, and insect venomanaphylaxis whose symptoms are not well controlled with avoidance measures and pharmacotherapy and in whom an IgE-mediated reaction to antigen has been documented ¹. Some recent reports have suggested that immunotherapy may also aid in atopic dermatitis ².

Allergy shots sometimes used for children with allergies to:

• things in the environment, like pollen, mold, or dust mites
• pet dander
• insect stings

Allergy shots aren’t helpful for food allergies. The best option for people with food allergies is to strictly avoid that food.

Allergy injections or allergen immunotherapy has been clinically demonstrated to provide long-term clinical benefits, including symptomatic disease remission and a reduction in allergic disease progression from rhinitis to asthma ³.

Aside from allergy shots, the other available treatment options for allergic diseases include aeroallergen avoidance and pharmacotherapy. In addition, surgery may be offered as an adjunct in appropriate patients (eg, septoplasty for nasal septal deviation, sinus surgery for chronic sinusitis, turbinate reduction for turbinate hypertrophy, nasal polypectomy for nasal polyps).

Effective treatment reduces symptoms and medication utilization while improving quality of life. Allergy shots has demonstrated long-term effectiveness in symptom reduction more than 3 years following treatment cessation and has prevented the development of new sensitizations in children.

Why are allergy shots used?

An allergy is when the body’s immune system overreacts to a usually harmless substance. Things that cause allergic reactions are called allergens. Common allergens include dust mites, molds, pollen, pets with fur or feathers, stinging insects, and foods.

The body reacts to the allergen by releasing chemicals, one of which is histamine. This release can cause symptoms such as wheezing, trouble breathing, coughing, a stuffy nose, and more. Some allergic reactions can be serious.

The best way to prevent or control allergy symptoms is to avoid allergens. Allergists (doctors who identify and treat allergies) look for causes of an allergic reaction with skin tests and blood tests. Based on the test results, they can recommend treatments, including medicines and ways to avoid allergens.

If these treatments don’t help, the allergist might recommend allergy shots.

Who can benefit from allergy shots?

Both children and adults can receive allergy shots, 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 allergist / immunologist first.

You and your allergist / immunologist should base your decision regarding allergy shots on:

• Length of allergy season and severity of your symptoms
• How well medications and/or environmental controls are helping your allergy symptoms
• Your desire to avoid long-term medication use
• Time available for treatment (allergy shots requires a significant commitment)
• Cost, which may vary depending on region and insurance coverage

Allergy shots are not used to treat food allergies. The best option for people with food allergies is to strictly avoid that food.

How do allergy shots work?

Allergy shots work like a vaccine. Your body responds to injected amounts of a particular allergen, given in gradually increasing doses, by developing immunity or tolerance to the allergen.

There are two phases:

1. Build-up phase. This involves receiving injections with increasing amounts of the allergens about one to two times per week. The length of this phase depends upon how often the injections are received, but generally ranges from three to six months.
2. Maintenance phase. This begins once the effective dose is reached. The effective maintenance dose depends on your level of allergen sensitivity and your response to the build-up phase. During the maintenance phase, there will be longer periods of time between treatments, ranging from two to four weeks. Your allergist / immunologist 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 allergy shots are successful, maintenance treatment is generally continued for three to five years. Any decision to stop allergy shots should be discussed with your allergist / immunologist.

How do allergy shots help?

Allergy shots help the body build immunity to specific allergens, so it’s not as bothered by them. Allergy shots also can help people who have allergies and asthma have fewer asthma flare-ups.

Allergy shots contain a tiny amount of a purified form of the allergen causing problems. Doctors increase the dose slowly over the first 3–6 months. This lets the immune system safely adjust and build immunity to the allergens. This is called the buildup phase.

The highest effective safe dose becomes that person’s monthly maintenance dose. Health care providers give this to patients for about 3 to 5 years. Most people will need fewer shots over time.

Some people’s allergy symptoms ease during the buildup phase. Others don’t feel better until they’re into the maintenance phase. After years of getting allergy shots, some may have lasting relief from symptoms.

Where should allergy shots be given?

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 in your allergist / immunologist’s office. If this is not possible, your allergist / immunologist should provide the supervising physician with comprehensive instructions about your allergy shot treatments.

Allergy shots risks and side effects

Allergy shots given by a trained health professional are safe and effective. Kids as young as 5 years old can get them.

A typical reaction is redness and swelling at the injection site. This can happen immediately or several hours after the treatment. Applying an ice pack to the area and taking an antihistamine can help. In some instances, symptoms can include increased allergy symptoms such as sneezing, nasal congestion or hives. More widespread reactions, like hives and itching all over the body, are less common. And more severe reactions (like wheezing, breathing problems, throat swelling, and nausea) are rare.

Serious reactions to allergy shots 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 office for at least 30 minutes after you receive allergy shots.

Before you or your child gets allergy shots, be sure to tell your doctor about any other medicines you or your child takes.

Complication prevention

While adverse systemic reactions are uncommon, allergy injections should be administered by only trained personnel, and resuscitative medications and equipment should be immediately available.

Adequate equipment and medications should be immediately available in case of anaphylaxis. The following are suggested equipment and medications for the management of systemic immunotherapy reactions. Modifications of this suggested list might be based on anticipated emergency medical services’ response time and physician’s airway management skills ⁴:

• Stethoscope and sphygmomanometer
• Tourniquet, syringes, hypodermic needles, and intravenous catheters (eg, 14-18 gauge)
• Aqueous epinephrine HCL 1:1,000 weight/volume
• Equipment to administer oxygen by mask
• Intravenous fluid setup
• Antihistamine for injection (second-line agents for anaphylaxis, but H1 and H2 antihistamines work better together than either one alone)
• Corticosteroids for intramuscular or intravenous injection (second-line agents for anaphylaxis)
• Equipment to maintain an airway appropriate for the supervising physician’s expertise and skill
• Glucagon kit available for patients receiving beta-blockers

How effective are allergy shots?

Allergy shots 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 allergy shots. If you have not seen improvement after a year of maintenance therapy, your allergist / immunologist will work with you to discuss treatment options.

Failure to respond to allergy shots 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.

Alternative to allergy shots

Aside from allergen immunotherapy, the other available treatment options for allergic diseases include aeroallergen avoidance and pharmacotherapy. In addition, surgery may be offered as an adjunct in appropriate patients (eg, septoplasty for nasal septal deviation, sinus surgery for chronic sinusitis, turbinate reduction for turbinate hypertrophy, nasal polypectomy for nasal polyps).

Sublingual immunotherapy

Sublingual immunotherapy experienced renewed interest in England after a review of safety and protocols of subcutaneous immunotherapy identified a 0.5%-5.6% rate of systemic reactions and fatalities, most commonly due to “preventable errors.” These findings reduced the use of subcutaneous immunotherapy in Britain and encouraged research into allergy treatment with sublingual immunotherapy. Most of the data address monotherapy, and research has yet to delineate ideal dosing concentrations, dosing schedules, dosing duration, and duration of patient response.

In sublingual immunotherapy, the theory is that the antigen comes into contact with Langerhans-like dendritic cells residing in the oral mucosa on the floor of the mouth under the tongue. These cells capture the antigen and migrate to local lymph nodes, resulting in the production of blocking antibodies and induction of T-regulator cells, which then suppress Th-1 and Th-2 cellular response via IL-10 and TGFβ mechanisms, both of which are described in detail above ⁵.

Sublingual immunotherapy has been demonstrated to decrease allergen-specific IgE, bronchial reactivity, and nasal and conjunctival eosinophils and neutrophils and to increase IgG4, IL-10, TGFβ, and interferon (INF)–gamma. Significant long-lasting symptom control of allergic rhinitis, rhinoconjunctivitis, and asthma has been demonstrated in multiple studies. This method is very convenient for patients, decreases blood and latex exposure, and is believed to be quite safe , although several cases of anaphylaxis have been reported in the literature ⁶.

References

1. Immunotherapy for Allergies. https://emedicine.medscape.com/article/1588289-overview
2. Cadario G, Galluccio AG, Pezza M, Appino A, Milani M, Pecora S, et al. Sublingual immunotherapy efficacy in patients with atopic dermatitis and house dust mites sensitivity: a prospective pilot study. Curr Med Res Opin. 2007 Oct. 23(10):2503-6.
3. NooN L. Prophylactic inoculation against hay fever. Int Arch Allergy Appl Immunol. 1953. 4(4):285-8.
4. Cox L, Nelson H, Lockey R, Calabria C, Chacko T, Finegold I, et al. Allergen immunotherapy: a practice parameter third update. J Allergy Clin Immunol. 2011 Jan. 127(1 Suppl):S1-55.
5. Francis JN, James LK, Paraskevopoulos G, Wong C, Calderon MA, Durham SR, et al. Grass pollen immunotherapy: IL-10 induction and suppression of late responses precedes IgG4 inhibitory antibody activity. J Allergy Clin Immunol. 2008 May. 121(5):1120-1125.e2.
6. Finegold I, Oppenheimer J. Immunotherapy: the next 100 years. Ann Allergy Asthma Immunol. 2010 Nov. 105(5):394-8.