Everything You Need to Know About Allergy Shots

Allergy shots don't cover all types of allergens. In general, however, they constitute a safe and effective treatment to control allergic reactions. They should only be administered at a medical center, as they could cause undesirable reactions.
Everything You Need to Know About Allergy Shots

Last update: 17 January, 2020

Allergy shots are one of the available treatments for allergic reactions. Some times they relieve symptoms. In other cases, they can even eliminate them after sustained treatment.

However, not everyone can get an allergy shot because there aren’t vaccines available for all forms of allergies. Immunotherapy is a field of study that’s still under development.

In any case, there are currently many myths around this and other vaccines. Keep reading to discover the truth about allergy shots, what they are used for, and their side effects.

What are allergies?

An allergy is an adverse reaction that occurs after ingesting certain substances or coming into contact with them. The number of substances that can cause allergic reactions is very wide. These substances are allergens that activate an excessive adverse reaction in the immune system. This, in turn, generates various effects.

Allergies can be mild or severe, and anaphylaxis is the most serious allergic reaction. It happens quickly and its symptoms are deadly.

What are allergy shots?

A person getting an injection.

Allergy shots are a treatment for allergies. Their objective is to reduce or eliminate a person’s hypersensitivity to certain substances that produce an allergic reaction when it isn’t possible to avoid them.

Also, allergy shots help the body develop immunity against the elements that generate an allergic reaction. Doctors only resort to immunotherapy when other treatments or measures aren’t enough to treat the problem.

How do allergy shots work?

Allergy shots contain a small amount of the allergen that causes an adverse reaction in a person. That allergen is present in a purified form inside the vaccine. When you inject it, the body produces antibodies that prevent the allergic reaction.

Gradually, doctors increase the dose until – in the best case – the body becomes immune to the allergen. Normally, a person requires a period of three to five years for the symptoms to visibly decrease or disappear.

How they’re administered

Usually, the mode of administration of allergy shots is intravenous. The treatment includes two phases:

  • The first phase is the accumulation stage. In this phase, you get a vaccine one to three times a week for a period of three to six months.
  • The second phase is the maintenance stage. It lasts between three and five years. In this phase, you get an injection either once a month or every six weeks. The doctor will evaluate your symptoms to determine when to stop treatment.

What types of allergy shots are there?

There are not vaccines for all types of allergens. For example, their application isn’t a good idea for food allergies. Vaccines are effective in cases of seasonal allergies, for indoor allergens (mites, mold, cockroaches or pet dander) and those caused by insect bites.

When should you get an allergy shot?

A medical practitioner preparing a shot.

Vaccines are good for people with a proven allergy through sensitization tests only. However, they’re not a good idea in the following cases:

  • Children under 5 years and pregnant women.
  • Patients with severe asthma or a cardiac condition.
  • People who take certain medications, particularly beta-blockers.
  • People with adverse reactions to the vaccine.

Vaccines are only a good idea if the other treatments don’t work. Often, doctors use them in the case of an allergy to insects, for example.

Do they have side effects? Are they safe?

Overall, most people have no problem when they get an allergy shot. However, some people have side effects. There might be redness, irritation, and inflammation on the spot where the vaccine was applied. However, they usually disappear soon.

Also, there are cases in which systemic reactions occur. This includes nasal congestion, sneezing or hives. Sometimes there’s throat inflammation and wheezing and chest tightness. In the most severe and rare cases, there may be anaphylaxis, as well. This is why you should always get the vaccine at a doctor’s office.

Expected results

Generally, there’s a moderate improvement during the first year of treatment. It’ll be more noticeable during the second year. In most cases, there are no symptoms during the third year, even if a patient no longer gets injections.

Some people will need more time and others will continue to have mild symptoms. When it comes to animal dander allergies, allergic people should avoid contact if at all possible.

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