allergy shots effects

Allergy shots or allergy immunotherapy is long-term medical treatment given to allergic individuals for prevention of allergic reactions to allergens.

Allergy is exaggerated immune responses in allergic individuals due to reaction of immune system to certain allergens. Allergy shots are given to individuals as a rehabilitation process for immune system, to diminish allergy symptoms and to decrease sensitivity to the allergens over time.


Allergy shots is recommended and often well tolerated for children age five and older. The immunotherapy can’t be initiated in pregnant women, but can be continued during pregnancy if initiated earlier. Medical condition (e.g. cardiac problems) should be considered when treating older people. You can ask a doctor online for more information regarding the therapy.

Allergy shots can be used to control symptoms of the following:

  • Hay fever
  • Eye allergy
  • Insect sting allergy
  • Mold, pet, cockroach or other allergy caused by indoor allergen
  • Allergic asthma


The following reasons are considered for taking allergy shots-

  • When medicine fails to work, leaving immunotherapy the only way to fight against allergy
  • When patients don’t like taking medicine to avoid its side effects
  • When patients prefer immunotherapy to medication to decrease long-term use of allergy medication


The mechanism of action of allergy shots is much like that of vaccine. Allergic individuals are given shots in their upper arm (tiny amount of the allergen they are allergic to). Body responds to injected allergen and produces specific antibody against those triggers. Amount of the injected dose is increased gradually, leading to gradual diminishment of production of allergic antibodies in the body against the triggers. Thus body develops tolerance or immunity to the allergen.

The schedule of allergy shots consists of two phases-

  • Build-up phase: involves gradual escalation of allergen dose and usually takes 3-6 months. A decrease in signs and symptoms is noticed during the build-up phase.
  • Maintenance phase: The phase begins when the effective dose is attained and usually continues for 3-5 years or longer.


The effectiveness of allergy immunotherapy depends on the dose of the allergen and the length of the treatment program. The following factors may lead to failure of the therapy-

  • Tremendous levels of triggers in the environment
  • Any unidentified allergen during the allergy evaluation
  • Insufficient dose of allergen in the injection

As the video shows, the best idea before any allergy shot is to visit your allergy specialist for having some medical advice.

Though rare, there’s a possibility of encountering an allergic reaction to the allergy immunotherapy. Three types of adverse reactions can occur with allergy shots-

Local: Local reaction can occur immediately or several hours after the treatment. Common local reactions include irritation, swelling and redness at the site of injection

Systemic: These reactions are less common, but more severe and affects a particular body system orthe entire body of individuals. Systemic reaction occurs with symptoms like-

  • Hives
  • Stuffy nose
  • Sneezing

Other more-severe reactions are:

  • Throat swelling and tightness
  • Wheezing
  • shock
  • Chest tightness

Anaphylaxis: It is an uncommon but potentially dangerous reaction to allergy shots and usually develops within 30 minutes of the allergy injections. Symptoms are:

  • Nausea and vomiting
  • Swelling of the throat and mouth
  • Difficulty breathing, speaking or swallowing
  • Fall in blood pressure
  • Collapse and loss of consciousness