Allergen Immunotherapy (AIT): Permanent Treatment For Lasting Allergy Relief

Allergen Immunotherapy (AIT)


Allergy shots are regular injections over a period of time, generally around 3 to 5 years, to stop or reduce allergy attacks. Allergy shots are a form of treatment called IMMUNOTHERAPY.

Each allergy shot contains a tiny amount of the specific substance that triggers your allergic reactions. These are called allergens.

Allergy shots contain just enough allergens to stimulate your immune system but not
enough to cause a full-blown allergic reaction.

Over time, your doctor increases the dose of allergens in each of your allergy shots. This helps get your body used to the allergens also known as DESENSITIZATION. Your immune system builds up a tolerance to the allergens causing your allergy symptoms to diminish over time. Allergy shots work by decreasing symptoms from particular allergens.


Allergy immunotherapy can be used to control symptoms triggered by:

  • If you have seasonal allergic asthma or have fever symptoms.
  • You may be allergic to pollens released by trees, grasses, or weeds.
  • If you have year-round symptoms, you may be sensitive to indoor allergens, such as dust
    mites, cockroaches, mold, or dander from pets such as cats or dogs.
  • Allergic reactions to insect stings can be triggered by bees, wasps, hornets, or yellow jackets.
  • Allergy shots are not available for food allergies or chronic hives, also known as urticaria.


Each injection contains small amounts of the allergen so that your body builds up immunity to it over time.

The process works much like taking a vaccine, where your body creates new antibodies to
combat the invasive substances.

Allergy shots also improve the way other immune system cells and substances function in response to allergens. Eventually, successful immunotherapy helps the body fight allergens and reduces adverse symptoms.

Allergy shots aim to decrease overall allergy symptoms over time. If you have allergic asthma, reduced asthma symptoms are also possible.


In some cases, allergy shots don’t work. This may be due to a variety of reasons, including–

1) Stopping treatment due to reactions.

2) Continued exposure to allergens at extremely high levels.

3) Not enough allergen in the actual shots.

4) Missed allergens during your initial evaluation.


In rare cases, allergy shots may cause a severe reaction, including—

  • Hives,
  • Swelling, and
  • Anaphylaxis.

If you go into anaphylactic shock, you may experience dizziness and breathing difficulties. This
reaction can develop within 30 minutes of receiving an allergy shot. This is why your doctor will likely ask you to stay at the office after the injection so that they can monitor you.


Most people don’t have much trouble with allergy shots, but they contain the substances that cause your allergies, so reactions are possible and can include–

1) Local reactions, which can involve redness, swelling, or irritation at the injection site. These
common reactions typically begin within a few hours of the injection and clear up soon after.

2) Systemic reactions, which are less common, but potentially more serious. You may develop
previously mentioned conditions, i.e., sneezing, nasal congestion, or hives.

3) More severe reactions may include throat swelling, wheezing, or chest tightness.

4) Anaphylaxis is a rare life-threatening reaction to allergy shots. It can cause low blood
pressure and trouble breathing. Anaphylaxis often begins within 30 minutes of the injection,
but sometimes starts later than that.


Allergy symptoms would not stop overnight. They usually improve during the first year of treatment, but the most noticeable improvement often happens during the second year.

Most people are desensitized to the allergens contained in the shots by the third year and no longer have significant allergic reactions to those substances.

After a few years of successful treatment—

  • Some people don’t have significant problems once AIT is stopped.
  • Some people have mild allergy episodes after AIT is stopped, but none is bothersome to the patient.
  • Other people need ongoing shots to keep symptoms under control.


Indicated for management of IgE-mediated disorders —

1) Allergic rhinoconjunctivitis.

2) Allergen-induced asthma.

3) Atopic dermatitis (eczema).

4) Fire ant hypersensitivity.

5) Food allergy.


1) Any medical conditions that would reduce a patient’s ability to survive a systemic allergic reaction or increase the risk of one.

2) Unstable asthma.

3) Coronary artery or other heart diseases.

4) Beta-blockers, ACE inhibitors.


Informed consent should include the following–

A) What the treatment is and alternatives to treatment.

B) Potential benefits and risks.

C) Costs associated with immunotherapy.

D) The anticipated duration of treatment.

E) Any specific office policies that affect treatment.


When you get an allergy shot, your allergist or doctor injects small doses of substances that you are allergic to (allergens) under your skin. This helps your body “get used to” the allergen, which can reduce or prevent symptoms.

At first, you may need to get allergy shots once a week and then once a month. It may take up to a full year of shots before you see any change in your symptoms.

The allergy shot may cause mild problems, such as soreness, redness, warmth, or swelling on the arm where you got the shot. It may also cause itching, hives, or a rash that spreads to other parts of your body.

How can you care for yourself at home?

1) Do not smoke or allow others to smoke around you. Smoking makes allergies worse. If
you need help quitting, talk to your doctor about stop-smoking programs and medicines.
These can increase your chances of quitting for good.

2) If there is a lot of pollution, pollen, or dust outside, stay inside and keep the windows
closed. Use an air conditioner when it’s hot outside, and use an air filter in your home.

3) If dust or dust mites trigger your asthma, decrease the dust around your bed.

4) Wash sheets, pillowcases, and other bedding in hot water every week.

5) Use dust-proof covers for pillows, duvets, and mattresses. Avoid plastic covers, because
they tear easily and do not “breathe.” Wash as instructed on the label.

6) Do not use any blankets and pillows that you do not need.

7) Use blankets that you can wash in your washing machine.

8) Consider removing drapes and carpets, which attract and hold dust, from your bedroom.

9) If mold triggers your allergies, get rid of furniture, rugs, and drapes that smell musty.

10) Check for mold under sinks and in the bathroom, attic, and basement. Use a dehumidifier
to control mold in these areas.

11) If pet dander triggers your allergies, keep pets outside or out of your bedroom. Old carpet
and cloth furniture can hold a lot of animal dander. You may need to replace them.

12) If your allergies are triggered by cold air, wear a scarf around your face, and breathe
through your nose.

13) Avoid colds and flu. Talk to your doctor about getting a pneumococcal vaccine shot. If
you have had one before, ask your doctor whether you need another dose. Get a flu
vaccine every year. If you must be around people with colds or the flu, wash your hands

When should you call for help?

You have symptoms of a severe allergic reaction. These may include:

  • Sudden raised, red areas (hives) all over your body.
  • Swelling of the throat, mouth, lips, or tongue.
  • Trouble breathing.
  • Passing out (losing consciousness). Or you may feel very lightheaded or suddenly feel
    weak, confused, or restless.
  • You have been given an epinephrine shot, even if you feel better.

Call your doctor now or seek immediate medical care if:

You have symptoms of an allergic reaction, such as:

– A rash or hives (raised, red areas on the skin).

– Itching.


– Belly pain, nausea, or vomiting.

– You do not get better as expected.


  1. Indraprastha Apollo Hospital, Delhi
  2. Rajiv Gandhi Cancer Institute and Research Centre, Delhi.
  3. Max Super Speciality Hospital, Delhi
  4. Dharamshila Narayana Superspeciality Hospital, Delhi
  5. AIIMS, Delhi
  6. Medanta The Medicity, Gurugram
  7. S.L. Raheja Hospital, Mahim, Mumbai
  8. Fortis Hospital, Mumbai
  9. Nanavati Hospital, Mumbai
  10. Jaslok Hospital, Mumbai
  11. Tata Memorial Hospital, Mumbai
  12. Apollo Hospital, Chennai
  13. Fortis Malar Hospital, Chennai
  14. Mazumdar Shaw Cancer Centre, Bangalore
  15. Christian Medical College, Vellore



This blog including information, content, references, and opinions is for informational purposes only.

The Author does not provide any medical advice on this platform.

Viewing, accessing, or reading this blog does not establish any doctor-patient relationship.

The information provided in this blog does not replace the services and opinions of a qualified medical professional who examines you and then prescribes medicines.

And if you have any questions of medical nature, please refer to your doctor or the qualified medical personnel for evaluation and management at a clinic/hospital near you.

The content provided in this blog represents the Author’s own interpretation of research articles.

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