Immunotherapy: Standard Build-Up vs. “Rush” Build-Up

Provided by David Hauswirth, MD

What is the difference between immunotherapy (IT) and rush immunotherapy?

Immunotherapy is a treatment for allergies.  The patient is given gradually increasing doses of a substance they are allergic to, trying to make them tolerant or not allergic.  For all types, the length of treatment is the same, typically 3-5 years.  The difference between “rush” and traditional immunotherapy is the buildup phase.  There are typically two phases to immunotherapy, build-up and maintenance. 

With “rush” immunotherapy, the build-up is accomplished in a rapid fashion.  Usually the patient will come into the office for a half or a whole day and receive many shots trying to build up more quickly.  There is a much higher risk of a systemic reaction with this type of treatment.  Rush is different from traditional build-up with weekly injections.  A third type is cluster immunotherapy with the patient receiving a few shots each visit trying to build a little faster.

Does rush immunotherapy work better than immunotherapy?

All of the immunotherapy styles have the same efficacy.  The only difference is how quickly you reach the maintenance dose.  A patient on rush, a patient on cluster and a patient on traditional immunotherapy will still be on the treatment for 3-5 years and will have the same outcome, regardless of the build-up schedule. 

Is rush immunotherapy as safe as immunotherapy?

There are more reactions to rush immunotherapy.  Patients will typically receive 4-12 shots in a day, significantly increasing the risk of a systemic reaction (anaphylaxis).  Traditional build-up is often favored because of a higher margin for safety.

Does the The American Academy of Allergy, Asthma & Immunology (AAAAI) have feelings either way about the use of Rush immunotherapy?

No system of build-up is endorsed by the AAAAI.  Cluster and rush immunotherapy are used in specific situations when the doctor feels it is appropriate to do so and is safe.  It is not appropriate for everyone.  Accelerated build-up (cluster and rush) is only FDA approved for venom immunotherapy.  This is a specific situation where a rapid push to maintenance is necessary for a life-threatening venom allergy.  Since allergic rhinitis is not life-threatening, the risk is often not reasonable.  Cluster and rush immunotherapy are not FDA approved and are technically off-label use.