Allergy shots, immunotherapy or hypo-sensitization is a procedure used by Allergists & Immunologists to decrease a patient’s reactivity toward his or her allergies. It has been in use since the early 1900’s and involves using fractional quantities of substances and increasing the dose over time to reduce or eliminate the allergic response to those substances.
Allergy shots can be used to treat symptoms such as:
While some allergists are attempting to develop safe immunotherapy to foods such as peanut, the technology is still experimental and not in general use.
The current theory of the mechanism of allergy shots is that it causes expansion of regulatory cells that calm allergic cells, keeping them from overreacting when they are exposed to allergenic substances. Allergic cells are not eliminated and patients can always still have an allergic reaction. However, the allergic reaction should be reduced if the series of shots was effective. Previously, it was believed that allergy shots cause development of blocking antibodies but it is now known that the effectiveness of allergy shots tend to occur before the blocking can be detected. Nonetheless, they may still have some role, for example, in the long-term efficacy of allergy shots.
Like vaccinations, allergy shots do not work for everyone. They can be up to 97% effective and some symptoms may disappear during part of the year whereas others may not or may be lessened but not disappear. Also, allergy shots have inherent risk. As patients are exposed to their own allergies, an allergic reaction, which can be severe and life-threatening, can occur. Nonetheless, allergy shots have been in use for many years and are known to be very effective and safe.
Side effects from allergy shots are local reaction to the suspension, which is common, as well as allergic reaction which can be severe and even life-threatening in rare cases. The severest of reactions are most common in patients with out-of-control asthma or breathing problems; during a severe allergy season; in those with a history of severe anaphylaxis; and in those taking certain medications and tend to occur within 30 minutes of the allergy shot injection.
Because allergic reactions can be severe and state-of-the-art knowledge is always changing, a patient should consider using an American Board of Medical Specialties Allergist & Immunologist when choosing who will oversee their treatment.