Allergy shots, also known as allergen immunotherapy, are a type of treatment designed to help alleviate the symptoms of allergies. This treatment involves injecting a person with small amounts of an allergen, such as pollen, dust mites, or pet dander for a while.

The goal of allergy shots is to help the person’s immune system build up a tolerance to the allergen, thereby reducing or even eliminating their allergic reactions. These are typically given in a doctor’s office and involve a series of injections given over several months or years.
Getting an allergy shot after a flu shot is generally safe and there is no evidence to suggest that it is harmful. In contrast, the flu shot is a vaccine that helps protect against the flu virus.
While there is no direct interaction between allergy shots and the flu vaccine, it’s important to keep in mind that both can cause some mild side effects.
For example, you may experience redness, swelling, or pain at the site of the injection. You may also develop mild flu-like symptoms after getting the flu vaccine, such as a low-grade fever, muscle aches, and fatigue.
Allergy shots work by gradually desensitizing the immune system to specific allergens that trigger an allergic reaction

Here is how these work:
- Identifying the Allergen: Your doctor will first identify the allergen(s) that are causing your allergic reactions by performing skin tests or blood tests.
- Preparing the Allergy Serum: Once the allergen(s) is identified, your doctor will prepare an allergy serum that contains a small amount of the allergen(s).
- Gradual Exposure: You will be given allergy shots containing gradually increasing amounts of the allergen(s) over time, typically over several months to years.
- Desensitization: As you receive the allergy shots, your immune system will gradually become desensitized to the allergen(s) so that you experience fewer or milder allergic symptoms.
- Maintenance Phase: Once you have reached a maintenance dose of the allergy serum, typically after several months of receiving allergy shots, you will continue to receive regular injections at that dose for several years.
Reactions to allergy shots
Allergy shots can be very effective at reducing the severity of allergy symptoms over time, but they can also cause some reactions.
Common reactions to allergy shots include:
- Local reactions: These are the most common reactions and occur at the injection site. They may include redness, swelling, and itching. These reactions are usually mild and go away within a few hours.
- Systemic reactions: These reactions can occur throughout the body and may include symptoms such as hives, itching, sneezing, and nasal congestion. Systemic reactions are less common than local reactions but can be more serious.
- Anaphylaxis: Anaphylaxis is a severe, life-threatening allergic reaction that can cause difficulty breathing, a drop in blood pressure, and loss of consciousness. Anaphylaxis is very rare, but it can occur after an allergy shot. For this reason, it is important to remain in the doctor’s office for 30 minutes after receiving an allergy shot to monitor for any signs of a reaction.

Conclusion
If you experience any type of reaction after an allergy shot, it is important to contact your doctor right away. Your doctor may adjust your allergy shot schedule or recommend additional treatments to manage your symptoms.