Allergen specific immunotherapy or commonly known as allergy shots is the only true long term treatment to relief your allergy and allergy related diseases that can last even after completing a shot program. It is done by gradually introduce allergens that you are allergic to under the skin to induce tolerance to those particular allergens. It works in 80-85% cases of pollen allergy and significantly decreases allergy symptoms compared to taking medications alone. It also prevents the fluctuation of symptoms seen during allergy seasons and even prevents you from developing new allergy while taking the shots. Build up phase takes about 3 - 6 months. During this time, you are given increasing amount of allergens to reach an effective dose. Maintenance phase takes 3 to 5 years. There is a small risk of developing anaphylaxis to allergy shots. That is why you are required to stay in the clinic for at least 20 - 30 minutes after getting the shots. Symptoms improvement of allergy shots depends on both the quality and throughoutness of the investigation phase and the treatment phase. In general, patient should see the improvement of allergy related symptoms in 2 to 3 months. After that, symptoms should continue to improve further. Many patients with strong sensitivities seen on allergy test might see clinical improvement very soon in the first month of treatment. In some cases, it might take up to a year to see a significant change in allergy related symptoms if patients do not react strongly to the allergens tested. With a good treatment plan, patients would expect to see significant improvement of nasal sinus symptoms very early in a few months. Other allergy related diseases like asthma, eczema, and lastly chronic recurrent hives would improve later. The reason to see this improvement is thought due to the inactivation of allergy cells that colonize at several places in our body like at the upper and lower airways, skin, and gut... A successful allergy desensitization process requires a good quality allergy test and a good quality allergy vaccine. Good quality allergy vaccine can be costly. It also carries higher risk of systemic reaction requiring patient's closed observation at an allergy clinic immediately after each treatment.
Allergy shots have been done safely as a cost-effective methods to treat and prevent complications from allergic diseases for over 100 years since it was first introduced by British physician Leonard Noon in 1911.