allergy immunotherapy side effects

3 min read 12-03-2025

Allergy immunotherapy, also known as allergy shots or sublingual immunotherapy (SLIT), is a powerful treatment option for many allergic conditions. It works by gradually desensitizing your body to allergens, reducing your symptoms over time. However, like any medical treatment, allergy immunotherapy comes with potential side effects. Understanding these side effects is crucial for making informed decisions about your treatment. This article will explore the common and less common side effects associated with allergy immunotherapy, helping you to discuss these possibilities with your allergist.

Common Side Effects of Allergy Immunotherapy

Most side effects of allergy immunotherapy are mild and manageable. They usually occur at the injection site or shortly after taking sublingual tablets.

Injection Site Reactions

Local Reactions: These are the most common side effects. They typically include redness, swelling, itching, or pain at the injection site. These usually resolve within a few hours.
More Severe Reactions: In rare cases, more severe reactions such as larger areas of swelling or hives may occur. These generally require monitoring by a medical professional.

Systemic Reactions (Allergy Shots)

Systemic reactions affect the whole body. These are less common but potentially more serious.

Mild Systemic Reactions: Mild reactions can include itching, hives, facial swelling, or mild shortness of breath. These usually respond well to simple antihistamines.
Serious Systemic Reactions: In rare instances, severe reactions like anaphylaxis can occur. Anaphylaxis is a life-threatening emergency requiring immediate medical attention. Symptoms include severe swelling, difficulty breathing, dizziness, and a rapid drop in blood pressure. Your allergist will carefully monitor you for any signs of serious systemic reactions.

Sublingual Immunotherapy (SLIT) Side Effects

SLIT, which involves taking tablets or drops under the tongue, generally produces milder side effects than injections. However, some individuals may still experience some discomfort.

Oral Irritation: Tingling, itching, or mild swelling in the mouth or throat are common.
Mild Allergic Reactions: Similar to injection-site reactions, mild allergic reactions such as itching, rash, or sneezing can occur.

Less Common but More Serious Side Effects

While rare, some more severe side effects can occur with allergy immunotherapy. These include:

Hypotension (low blood pressure): Although uncommon, a drop in blood pressure can occur, especially during or shortly after an injection.
Cardiac arrhythmias (irregular heartbeat): In rare cases, immunotherapy can trigger irregular heartbeats. This is more likely in individuals with pre-existing heart conditions.

It's important to note: The risk of serious side effects is low, and your allergist will take precautions to minimize these risks. They will carefully monitor your reactions, adjust the dosage as needed, and provide guidance on managing any potential problems.

When to Seek Immediate Medical Attention

Seek immediate medical attention if you experience any of the following after receiving allergy immunotherapy:

Difficulty breathing or wheezing
Severe swelling of the face, lips, or throat
Dizziness or lightheadedness
Rapid heartbeat
Loss of consciousness

Managing Side Effects

Most side effects can be managed with simple measures, such as:

Over-the-counter antihistamines: These can help relieve itching, swelling, and other mild symptoms.
Cold compresses: Applying a cold compress to the injection site can help reduce swelling and pain.
Monitoring for reactions: Pay close attention to your body after each treatment and report any unusual symptoms to your allergist immediately.

Conclusion: Weighing the Benefits and Risks

Allergy immunotherapy offers significant long-term benefits for many allergy sufferers. While there are potential side effects, the vast majority are mild and manageable. Your allergist will carefully assess your individual risks and benefits before initiating treatment. Open communication with your allergist is vital throughout the process to ensure your safety and comfort. Remember to report any concerns promptly to maximize the effectiveness and minimize the risks of allergy immunotherapy. Understanding these potential side effects empowers you to make an informed decision about your treatment options and work collaboratively with your healthcare provider to achieve the best possible outcome.