
Allergy shots, also known as subcutaneous immunotherapy (SCIT), have been used for over 100 years. They help reduce allergy symptoms. An allergy shot contains a small amount of an allergen, like mold spores or pollen.
We will look into how allergy shots work and what you can expect. Knowing the side effects and how often you need allergy shots is key to good health.
Key Takeaways
- Allergy shots are a long-term treatment that aims to desensitize patients to specific allergens.
- The build-up phase typically lasts 3-6 months with injections 1-2 times per week.
- The maintenance phase continues for 3-5 years with injections every 2-4 weeks.
- Common reactions are localized at the injection site and usually resolve quickly.
- Serious reactions like anaphylaxis are rare but require medical supervision.
Understanding Allergy Shots (Subcutaneous Immunotherapy)

Allergy shots, also known as subcutaneous immunotherapy, are a long-term treatment. They aim to make your body less sensitive to specific allergens. You get small, controlled amounts of the allergen over time, building up tolerance.
The goal of allergy shots is to change how your immune system reacts. This can greatly reduce or even stop allergic reactions. People can then enjoy outdoor activities or be around pets without worrying about an allergic reaction.
What Are Allergy Shots and How Do They Work?
Allergy shots work by slowly increasing the amount of the allergen you’re exposed to. At first, you get injections once or twice a week. This phase can last several months.
Then, the shots are given less often, every 2-4 weeks. You start with a small dose of the allergen. It’s increased with each shot. This helps your body get used to the allergen, making reactions less severe over time.
History and Effectiveness of Immunotherapy
Allergy immunotherapy has been around for over a century. It has improved a lot over the years. It’s effective in treating allergic rhinitis, asthma, and insect sting allergies.
Research shows that allergy shots can lead to long-term tolerance and a big drop in symptoms. In some cases, they can even cure the allergy. How well it works depends on the allergy type, symptom severity, and how you react to the treatment.
Common Allergy Injection Side Effects and Reactions

Allergy shots can cause side effects, which are divided into local and systemic reactions. It’s important for patients to know about these side effects. This knowledge helps them make better choices about their treatment.
Local Reactions at the Injection Site
Most side effects of allergy shots happen at the injection site. These can include redness, swelling, or itching. Over 70% of patients experience these reactions, but they are usually mild. They often get better as treatment goes on.
In some cases, reactions can be more serious. But, they can be treated with antihistamines or other medicines. Your healthcare provider will tell you what to do.
Systemic Reactions to Allergy Shots
Systemic reactions are less common but can be more serious. These reactions affect the whole body, not just the injection site. Symptoms can include breathing problems, skin issues, or rarely, anaphylaxis. These reactions need immediate medical help if they are severe.
But, serious systemic reactions are rare. Doctors watch patients closely to lower risks. Following the treatment plan and talking to your doctor about any issues can help. This way, you can get the most from allergy shots while avoiding bad reactions.
Allergy Shot Schedule: Frequency and Timeline
Many people wonder how often and for how long they need allergy shots. The treatment is split into two phases: build-up and maintenance. Knowing about these phases helps manage expectations and stick to the treatment plan.
Build-up Phase: Once or Twice Weekly Injections
In the build-up phase, shots are given once or twice a week. This phase lasts 3 to 6 months. It involves gradually increasing the allergen dose to build tolerance. The Medical organization says this phase is key for finding the right dose for the maintenance phase.
Doctors explain, “The build-up phase helps the body get used to the allergen. This reduces allergic reactions over time.”
Source: Medical organization
Maintenance Phase: Every 2-4 Weeks
After the build-up phase, shots are given every 2 to 4 weeks. This phase can last 3 to 5 years. It aims to keep the body tolerant of the allergen and prevent symptoms.
| Phase | Frequency | Duration |
| Build-up Phase | Once or twice weekly | 3 to 6 months |
| Maintenance Phase | Every 2-4 weeks | 3 to 5 years |
Total Treatment Duration and Expectations
The length of allergy shot treatment varies. Some may need 3 years, while others may require 5 years or more. It’s important to remember that allergy shots are a long-term commitment. Sticking to the schedule is key for the best results.
Monitoring Period After Injections
After each shot, patients are watched for 20 to 30 minutes for any bad reactions. This monitoring is vital for safety and quick response to any issues.
Understanding the allergy shot schedule helps patients prepare for the long-term commitment. It also helps them make informed decisions about their care.
Conclusion: Making Informed Decisions About Allergy Immunotherapy
Understanding the side effects and treatment schedule of allergy shots is key. This knowledge helps patients make smart choices about their allergy treatment. Allergy shots can offer lasting relief for those with chronic allergies, lasting three to five years.
When getting allergy shots, patients might face local or systemic reactions. These could include symptoms at the injection site or body-wide reactions. Sometimes, a fever can occur after a shot. It’s vital to talk to a healthcare professional about the treatment schedule and frequency.
It’s wise to talk to a healthcare professional about allergy shots. They can explain how often shots are given and what to expect. Knowing the possible side effects and treatment plan helps patients make informed choices. This way, they can find lasting relief from chronic allergies.
FAQ:
What are allergy shots and how do they work?
They are immunotherapy injections that gradually expose you to allergens to retrain your immune system and reduce allergic reactions over time.
What are the common side effects of allergy shots?
Mild redness, swelling, itching, or soreness at the injection site and occasional sneezing or fatigue.
How often should I get allergy shots?
1–2 times per week during the build-up phase and every 3–4 weeks during maintenance.
How long do I need to take allergy shots?
Usually for 3–5 years to achieve long-term benefit.
Can allergy shots make me sick?
They may cause mild flu-like or allergy-type symptoms, but true illness is uncommon.
What is the monitoring period after allergy shots?
You are typically observed in the clinic for about 20–30 minutes for immediate reactions.
How often can I get allergy shots?
They are given weekly at first, then monthly once maintenance dosing is reached.
What are the systemic reactions to allergy shots?
Whole-body allergic reactions such as hives, wheezing, throat swelling, dizziness, or low blood pressure.
Can I experience fever after an allergy shot?
A mild low-grade fever can occur rarely, but persistent or high fever should be reported to your doctor.
References:
National Center for Biotechnology Information. Evidence-Based Medical Insight. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC3683521/