Allergy shots, also known as allergen immunotherapy, are a long-term treatment designed to reduce or eliminate allergy symptoms. This approach involves a series of injections that help the body build tolerance to specific substances. While generally safe, allergy shots involve exposure to allergens, raising questions about potential adverse reactions. The primary goal is lasting relief from allergies, often reducing the need for daily medication.
Understanding Allergy Shots
Allergy shots gradually introduce increasing amounts of specific allergens to re-educate the immune system, shifting its response from an allergic reaction to tolerance. The body produces antibodies like IgG4, which block allergic reactions.
The process involves two phases: a build-up phase and a maintenance phase. During the build-up phase, injections are given frequently (one to three times weekly) with gradually increasing dosage, lasting three to six months. Once an effective dose is reached, the maintenance phase begins, with injections given monthly for three to five years or longer. This long-term commitment allows the immune system to develop sustained immunity, often providing lasting benefits after treatment.
Potential Reactions and Side Effects
While generally safe, allergy shots can cause reactions because they contain the substances that trigger allergies. These reactions range from mild to, in rare cases, life-threatening.
Local reactions are the most common, occurring at the injection site with redness, swelling, or itching that resolves quickly. These mild reactions indicate the body’s response.
Systemic reactions are less common but more widespread and serious. Symptoms include sneezing, nasal congestion, hives, throat itching or tightness, flushing, or lightheadedness. More severe systemic reactions might involve wheezing, chest tightness, or difficulty breathing. Most systemic reactions are mild and respond to treatment, but require immediate attention.
Anaphylaxis is the most severe, life-threatening systemic reaction, though very rare. It can cause a dangerous drop in blood pressure and significant breathing difficulties. Anaphylaxis typically begins within 30 minutes of the injection, highlighting the importance of post-injection observation. Medical professionals are trained to recognize and manage this emergency.
Minimizing Risks During Treatment
To ensure patient safety, immunotherapy injections are always administered in a medical setting by trained healthcare professionals. This ensures immediate medical assistance if a reaction occurs. A mandatory 20 to 30-minute observation period is required after each injection. This allows medical staff to monitor for immediate reactions, particularly systemic or anaphylactic responses.
If a reaction occurs, emergency medications, including epinephrine, are readily available and administered promptly. Patients are advised to carry an epinephrine auto-injector for use if a delayed severe reaction occurs after leaving the clinic.
Dosage adjustments are important for risk management. The allergen dose is gradually increased during the build-up phase, considering patient tolerance and observed reactions. If a patient misses scheduled doses, they may need to return to a lower dose to prevent severe reactions upon resuming treatment. Patients are also educated on symptoms to look for and encouraged to report any concerns or reactions immediately to their medical team.
When Allergy Shots Are Not Recommended
Allergy shots are not suitable for everyone. Certain conditions or medications can make the treatment unsafe or less effective. Individuals with uncontrolled or severe asthma may not be good candidates, as allergy shots can potentially worsen asthma symptoms. Those with certain heart conditions or other significant medical issues should discuss these thoroughly with their allergist.
Beta-blockers, used for heart conditions and high blood pressure, can prevent epinephrine from working effectively. Since epinephrine is the primary treatment for severe allergic reactions, taking beta-blockers increases the risk of an untreatable severe reaction, making allergy shots unsafe.
Starting new immunotherapy during pregnancy is generally advised against. However, continuing the maintenance phase under medical supervision is often acceptable if already tolerating treatment. Children under five years of age are generally not recommended for allergy shots, partly due to difficulty communicating adverse symptoms.