Immunotherapy Allergen Desensitization/Allergy Shots

For peo­ple who have aller­gic rhini­tis or asth­ma, immunother­a­py may be a crit­i­cal part of treat­ment. Over the course of ther­a­py it often improves symp­toms and lessens the need for med­ica­tion. Immunother­a­py is often the main­stay of treat­ment for indi­vid­u­als with an aller­gy to sting­ing insects. Immunother­a­py is not well proven for oth­er aller­gic dis­eases, such as atopic der­mati­tis (eczema) and urticar­i­al (hives). It is nei­ther safe nor effec­tive for a food allergy. 

Think of immunother­a­py as a ​“vac­ci­na­tion” against aller­gies. How­ev­er, unlike a sin­gle shot you might get for tetanus or the flu, immunother­a­py involves reg­u­lar admin­is­tra­tion of increas­ing amounts of the sub­stances that cause your aller­gies. This repro­grams the way we respond to those aller­gy triggers. 

Immunother­a­py involves giv­ing reg­u­lar, sub­cu­ta­neous injec­tions of the same inhalant sub­stances or insect ven­oms that are respon­si­ble for an individual’s symp­toms. A great deal of research has been done to deter­mine exact­ly how this process works to sup­press aller­gic dis­eases. It appears that the reg­u­lar expo­sure to minute, but grad­u­al­ly increas­ing, amounts of sub­stances can ​“retrain” or ​“rebal­ance” an individual’s immune sys­tem not to respond to these triggers. 

Aller­gy shots are giv­en year-round for max­i­mum ben­e­fit. At the start of treat­ment, aller­gy shots are giv­en once or twice per week under direct physi­cian super­vi­sion. Over the next 7 – 10 months, the amount of aller­gen in each injec­tion is increased until a ther­a­peu­tic lev­el is reached. Once the ther­a­peu­tic lev­el is reached, the injec­tion fre­quen­cy is grad­u­al­ly extend­ed to every 4 weeks. Most aller­gists give immunother­a­py, to both inhalants and insect ven­oms, for 4 or 5 years total. Immunother­a­py of this dura­tion is much more like­ly to result in long term improve­ment in aller­gic dis­ease than short­er courses. 

Immunotherapy/​allergy shots are giv­en in grad­u­al­ly increas­ing dos­es for a good rea­son. Larg­er dos­es giv­en too quick­ly can cause aller­gic reac­tions that may be fright­en­ing or even life threat­en­ing. It is safe to miss a dose or two (every­one has vaca­tions or emer­gen­cies), but this can slow down the dose build-up process. How­ev­er, if a great length of time exists between injec­tions, it may be nec­es­sary to decrease the amount and the con­cen­tra­tion of the injec­tion. This is done to pro­tect you from hav­ing a seri­ous aller­gic reaction. 

Most peo­ple notice improve­ment after 6 to 12 months. There are rare indi­vid­u­als who improve soon­er than 6 months and there are oth­ers who need immunother­a­py for up to two years to start to improve. Once improve­ment begins, there is gen­er­al­ly con­tin­u­ous improve­ment for sev­er­al more years. 

Also, keep in mind that a few peo­ple do not ben­e­fit from immunother­a­py. Unfor­tu­nate­ly, it is impos­si­ble to pre­dict who will not respond to immunother­a­py. If some improve­ment is not not­ed with­in two years, the immunother­a­py is unlike­ly to be effec­tive and is, there­fore discontinued. 

Suc­cess­ful immunother­a­py results in improve­ment in aller­gic dis­ease. Indi­vid­u­als with aller­gic rhini­tis or asth­ma may become symp­tom-free, but often need to con­tin­ue some med­ica­tions. These med­ica­tions, how­ev­er, are com­mon­ly at much low­er dos­es than before immunother­a­py. It has also been shown to decrease the risk of devel­op­ing asth­ma by as much as 50%. While indi­vid­u­als with ven­om aller­gy may become insen­si­tive to sting­ing insect bites, they should always car­ry emer­gency med­ica­tion, even after immunother­a­py, if instruct­ed to do so by a physician. 

Sources:

Amer­i­can Col­lege of Aller­gy, Asth­ma, and Immunol­o­gy (acaai​.org)

The Amer­i­can Acad­e­my of Aller­gy, Asth­ma & Immunol­o­gy | AAAAI