Allergy shots, a long-term immunotherapy, reduce or prevent allergic reactions. While generally safe and effective, individuals may experience mild, temporary side effects, indicating the body is responding to therapy.
How Allergy Shots Work
Allergy shots gradually introduce increasing amounts of specific allergens into the body. This desensitizes the immune system over time, helping it tolerate them rather than overreacting.
This immunotherapy modifies the body’s immune response towards a more tolerant state. The treatment involves a “buildup phase” with frequent, increasing doses, followed by a “maintenance phase” of less frequent, consistent doses. This gradual exposure reduces allergic symptoms.
Common Reactions to Allergy Shots
After receiving an allergy shot, individuals can experience a range of reactions, most of which are mild and temporary. The most common responses are local reactions at the injection site, such as redness, swelling, or itching. These usually appear within a few hours and resolve quickly.
Beyond local effects, some people may experience mild systemic reactions, which affect the entire body. These can include symptoms like sneezing, nasal congestion, or mild hives. While not always listed as a primary side effect, fatigue can also occur as a common, albeit usually mild and temporary, systemic reaction. These reactions often indicate that the immune system is actively engaging with the injected allergens, a necessary part of building tolerance.
Understanding Why Fatigue Can Occur
Fatigue experienced after an allergy shot often stems from the body’s active immune response to the introduced allergens. When the immune system encounters these substances, it initiates a complex process to build tolerance, which demands energy. This heightened activity can temporarily deplete the body’s energy reserves, leading to feelings of tiredness or sluggishness.
The body’s processing of injected allergens can also involve the release of inflammatory mediators, such as histamine. While histamine is known for its role in allergic reactions, it can also contribute to feelings of drowsiness and general malaise. Essentially, the immune system is working diligently to adapt and modify its response, making this an energy-intensive process that can result in temporary fatigue.
Managing Post-Shot Fatigue and When to Seek Medical Advice
To help manage fatigue and other mild reactions after allergy shots, several practical steps can be taken. Resting adequately and ensuring proper hydration before and after the shot can support the body’s recovery. Avoiding strenuous physical activity immediately following the injection is also often recommended. Maintaining a balanced diet can further aid the body in processing the allergens and recovering energy.
It is important to communicate any persistent or concerning fatigue with your allergist. While mild fatigue is common, prolonged or severe tiredness should be discussed to determine if adjustments to the treatment plan are needed. More serious symptoms, such as severe widespread hives, difficulty breathing, throat swelling, dizziness, or a rapid heart rate, require immediate medical attention. These severe reactions are rare but necessitate prompt professional evaluation.