Cluster Immunotherapy

Rapid Build Up Immunotherapy Schedules

Female nurse filling syringe
Cluster immunotherapy can get your allergy symptoms better quickly.. Hero Images/Getty Images

What is Immunotherapy?

Immunotherapy, or allergy shots, offers the only potential cure for allergic rhinitis, allergic conjunctivitis, allergic asthma, atopic dermatitis and venom allergy. Unlike medications that simply cover up allergic symptoms, allergy shots are the only therapy to change how a person’s body reacts with allergies. Since immunotherapy is the only treatment that comes the closest to a cure for allergies, one would think that everybody with allergies would want to do it.

However, 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 they start working.

The method of receiving immunotherapy consists of starting at a low dose that should not cause an allergic reaction, with slowly advancing the dosage until the person becomes tolerant to large amounts of the extract. This is called the “build-up phase”. These injections are initially given once to twice a week until a constant dose is achieved. This is called the “maintenance phase” or “maintenance dose”. Reaching the maintenance dose usually takes approximately 3 to 6 months. Once the maintenance dosage is reached, the allergic symptoms are largely resolved in most patients. Thereafter, the injections are given every two to four weeks.

The risks of immunotherapy consist of the possibility of experiencing an allergic reaction to the allergy shot.

Most allergic reactions consist of mild to moderate swelling and itching at the site of the injection. These reactions occur frequently, but rarely require any change in treatment. A large swelling may require an adjustment of the immunotherapy dosage or a change in the frequency and amount of the shots.

Less commonly patients experience whole-body allergic reactions, sometimes called “anaphylaxis”. Most of these reactions are mild and consist of itching of the skin, hives, or runny nose. Others are more severe and can present as cough, chest tightness, wheezing, throat tightness, shock and rarely can be life threatening. For this reason, it is normally required that patients remain in the physician’s office for 30 minutes after the injection since most reactions occur during this time. These reactions are usually easily reversed with medicines such as injectable epinephrine and antihistamines.

What is Cluster Immunotherapy?

Rapid build-up schedules for allergy shots are used by some allergists in order to achieve a higher dose of allergy shots faster, which result in 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.

Cluster immunotherapy involves giving two or more allergy shots at each visit, usually spaced apart by 30 minutes. This procedure is performed once or twice a week, and also allows for a person to get to their maintenance dose much quicker. While some studies have shown that cluster immunotherapy results in higher rates of allergic reactions than traditional schedules for allergy shots, other studies show no difference for rates of allergic reactions. Some allergists recommend medications, such as antihistamines, to minimize these reactions during cluster immunotherapy, while others do not.

Both rush and cluster immunotherapy offer an alternative to traditional schedules for allergy shots, allowing a person to achieve higher doses of allergy shots much quicker, and therefore get benefit sooner. However, both forms probably result in an increased rate of allergic reactions, particularly for rush immunotherapy. And, both are more of a time commitment up front, with rush immunotherapy typically taking a full day (or more), and cluster immunotherapy taking an hour or more for every visit initially.

Rush and cluster immunotherapy are commonly used for people with venom 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 problem with allergic reactions to their allergy shots. Often, allergists have typical ways of giving allergy shots to their patients, and they tend to offer this typical build-up style to all of their patients. Most allergists don’t simply give their patients the choice of build-up schedule. 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.


Serota M, Portnoy JM. Subcutaneous Aeroallergen Immunotherapy: Accelerated Schedules (Cluster and Rush). UpToDate. 2014.

Cox L. Advantages and Disadvantages of Accelerated Immunotherapy Schedules. J Allergy Clin Immunol. 2008;122:432-4.

DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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