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Q. Does taking an antihistamine before getting allergy shots impact the effectiveness of the immunotherapy? I have seen occasional recommendations to take one in order to avoid a bad reaction, but I have not been able to find an answer to this concern. In addition, is it a problem if a patient has been doing this consistently, and then stops taking the antihistamine? Would it increase the chance of a negative reaction?

A. Data from immunotherapy for venoms suggests that antihistamine pre-treatment during the rapid build-up phase of immunotherapy reduces local adverse symptoms related to venom injections such as redness, swelling, and itching.  A 2001 study looked at the question of whether antihistamine therapy influenced the effectiveness of honeybee immunotherapy. Results of the 2001 study, conducted after patients were on venom immunotherapy for an average of 3 years, suggested that pre-treatment with antihistamines during the initial phase of immunotherapy improved the effectiveness of the immunotherapy.

Some allergists recommend pre-treatment with oral antihistamines with the goal of prevention of local adverse symptom at the site of allergen immunotherapy injections.  If a patient had been consistently taking antihistamines prior to immunotherapy, and stopped taking the antihistamines prior to immunotherapy, it is possible that they might have increased local irritation related to immunotherapy injections.  However, it is also possible that the patient might not experience increased local irritation related to immunotherapy injections.

I recommend that you discuss your specific history and your concerns with your allergist, in order to develop a plan that is personalized for you.

Q. My 15-year-old son has peanut allergy. Is SLIT available at this time as a treatment for this?

A. Unfortunately, there is no definitive treatment for peanut allergy at this time. Researchers continue to study desensitization methods to include oral dosing and epicutaneous (delivered to the skin through a patch) delivery.

The National Institutes of Health (NIH) did sponsor a study on sublingual immunotherapy (SLIT) for peanut allergy, which was published in 2013. This study did show promise, and many patients were able to consume more peanut powder at the end of the study than at the beginning of the study. 

Although these results were very encouraging, none of the patients who were treated with SLIT for 44 weeks were able to undergo a desensitization challenge without symptoms.

Your son’s allergist can help keep you updated on emerging research and methods, and help your family consider further strategies that may be helpful for your son’s care.

Q. Can long term allergy treatments provoke the body to become allergic to other things? My husband is following a 3 year anti-allergy program and he seems to have worse symptoms than before. In other words, he is now allergic to things he cannot identify.

A. Allergic sensitization generally increases over time, from childhood to adulthood.

Allergen immunotherapy (also called “allergy shots” or “AIT”) involves the administration of gradually increasing quantities of specific allergens until a dose is reached that is effective in reducing symptom severity from natural exposure (similar to a vaccine). The major objectives of allergen immunotherapy are to reduce responses to allergic triggers that precipitate symptoms in the short term and to decrease inflammatory response and prevent development of persistent disease in the long term. Data on allergen immunotherapy in children are interesting, as immunotherapy may prevent development of new sensitizations in children.

It is certainly possible that your husband has developed new sensitizations over time. Alternatively, perhaps with treatment of symptoms triggered by allergens, symptoms related to non-allergic triggers such as respiratory irritants or infections may be relatively more prominent. Allergen immunotherapy is not thought to provoke new sensitizations.

Your husband should discuss his symptoms, and potential strategies for managing symptoms, with his allergist.