Rush and Cluster Immunotherapy Risks

You may have heard that rush immunotherapy and cluster immunotherapy are ways to get control of your allergies more rapidly, with less of a time commitment down the line. What are these procedures, what are the advantages and disadvantages, and when are these alternative approaches most beneficial? What do you need to think about to make the best decision?

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Immunotherapy for Allergies and Asthma

Immunotherapy, or allergy shots, are highly effective for allergic rhinitis, allergic conjunctivitis, atopic dermatitis, allergic asthma, and venom allergy. Unlike medications that simply cover up allergic symptoms, allergy shots are the only therapy to change how a person’s body deals with allergies before symptoms develop. You would think, therefore, that everyone would want to do allergy shots. Unfortunately, allergy shots can be inconvenient for many people because they involve a significant time commitment (typically going to the allergist’s office once to twice a week initially), and may take months before patients notice any improvement in symptoms.

Rapid build-up (accelerated) schedules for allergy shots are used by some allergists in order to achieve a higher dose of allergy shots faster, which results in the benefit of the shots sooner. These schedules also result in a person getting to a “maintenance dose” faster, as well as being able to come into the allergist’s office less often for allergy shots once this maintenance dose is achieved. There are two types of rapid build-up schedules—rush immunotherapy and cluster immunotherapy.

What Is Rush Immunotherapy?

Rush immunotherapy involves giving a person multiple allergy shots over a period of many hours to days, achieving a maintenance dose in a very short amount of time. Most often, increasing doses are given every 15 to 60 minutes over a period of one to three days in the beginning and then increased rapidly to get to maintenance doses.


Rush immunotherapy allows people to get up to maintenance doses of their allergy shots much more rapidly. This is often reached in a period of a few days. In contrast, with conventional allergy shots, people usually receive single doses once or twice a week, and it can take three to six months to build up to maintenance doses. After the initial period of rush immunotherapy, a person is able to come into the allergist’s office typically only once a week for the next few weeks, then even less often.

People undergoing rush immunotherapy also achieve benefit from allergy shots much faster, usually within a few weeks. The benefit with standard allergy shots can take much longer, with benefits usually beginning around the time in which maintenance doses are achieved.

Rush immunotherapy is commonly used for people with venom allergy (e.g., bee sting allergies and fire ant sting allergy). This allows for quicker protection against allergic reactions to future insect stings, and may actually be a safer way to treat people with venom allergies who have had a problem with allergic reactions to their allergy shots. A 2016 study found rush immunotherapy to also be safe and more efficient for venom allergies in children as compared to adults.

Over the long run, rush immunotherapy may also be more cost-effective.

Not all patients will qualify for rush or cluster immunotherapy. These treatments are not recommended for people with certain other comorbid conditions, such as poorly controlled asthma or serious cardiac conditions.


Unfortunately, rush immunotherapy results in an increased rate of allergic reactions (including anaphylaxis) in a large percentage of people, so various medications (such as antihistamines and corticosteroids) are often given in order to prevent or minimize these reactions. A person undergoing rush immunotherapy should be prepared to spend at least a couple of days in the allergist’s office, receiving many allergy shots over this time.

Rush is more of a time commitment up front, typically taking a full day or more, while it often decreases the time commitment later on.

What Is Cluster Immunotherapy?

Cluster immunotherapy falls somewhere between conventional immunotherapy and rush immunotherapy in dose escalation. With cluster immunotherapy, most often two to three injections (of increasing doses) are given at each visit. It's thought that with this technique, maintenance dosing can be achieved by four to eight weeks (in contrast to three to six months). As with rush immunotherapy, this approach allows a person to reach maintenance dosing more rapidly but carries a higher risk of reactions. Usually, fewer total injections are required overall than with standard immunotherapy

Bottom Line

Rush and cluster immunotherapy offer an alternative to traditional schedules for allergy shots, allowing a person to achieve higher doses of allergy shots much more quickly, and therefore get benefit sooner. However, rush immunotherapy probably is associated with an increased rate of allergic reactions. Rush is more of a time commitment up front, typically taking a full day or more, whereas it can be a time saver later on.

Often, allergists have typical ways of giving allergy shots to their patients, and they tend to offer a standard build-up style to all of their patients. Most allergists don’t give their patients the choice of a build-up schedule, and many private practice offices may not be equipped to offer it. If you are interested in pursuing one of these rapid build-up schedules, contact several allergists in your area to find one who is experienced in these procedures.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. UT Southwestern. Rush immunotherapy: faster relief for tough allergy symptoms.

  2. Confino-Cohen R, Rosman Y, Goldberg A. Rush venom immunotherapy in childrenJ Allergy Clin Immunol Pract. 2017;5(3):799-803. doi:10.1016/j.jaip.2016.10.011

  3. Allergy & Asthma Care P.A. Cluster immunotherapy: rapid desensitization.

Additional Reading

By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.