Allergy Shots: 100 Years and Counting
By Karen Gregory, DNP, RRT, FAARC
Allergies are diseases of the immune system that cause an overreaction to a specific substance. People who have allergies have an immune system that reacts to a usually harmless substance in the environment. These allergens can trigger sneezing, itchy and runny nose, itchy and watery eyes, and in some cases, coughing and wheezing. Allergies are not only bothersome, but many have been linked to respiratory illnesses, including asthma.
Allergy shots, also known as “immunotherapy,” refer to the injection of increasing doses of a precise amount of allergen. The treatment is aimed at building a tolerance to a substance that triggers symptoms. These substances can include grass, trees, and ragweed and other weed pollens; mold, dust, and pet dander; or in some cases stinging insects.
The allergy injections increase weekly until the maintenance dosage is achieved. Over a period of time, the body’s immune system will hopefully become less sensitive to the substance, resulting in reduced or eliminated allergy symptoms.
A long history
It’s been a little over 100 years since Leonhard Noon and John Freeman published their pioneering works on allergy shots, also known as “allergen-specific immunotherapy,” using grass pollen extracts. In 1911, Noon and Freeman successfully treated patients who had hay fever by injecting them with pollen extracts at St. Mary’s Hospital in London, England, and the modern era of allergy shots was born.
The road to their discoveries, however, is much longer. Traveling back to 2641 BC, we find King Menes of Egypt was said to have died after being stung by a wasp, making this event the first recorded occurrence of anaphylactic shock. Ancient people believed that allergic reactions were brought about by evil spirits and curses because of their mystifying nature.
In 1819, John Babcock, an English physician, described “hay fever” as a disease of the upper respiratory tract. The first “allergy shot” to treat hay fever was actually administered in 1869 when Charles Blackley performed allergy testing on himself by putting pollen directly into a cut in his skin. Blakely found that a positive reaction to a specific allergen could be recognized within 20 minutes by the appearance of “hives” at the site.
Clemens Von Pirquet became aware that some patients with diphtheria developed non-disease related symptoms when treated with a horse serum antitoxin, which coined the term “allergy” in 1906 in Vienna, Austria.
By 1937, Daniel Bover synthesized the first antihistamine, diphenhydramine. Up until this time period, allergy shots were the only available allergy remedy.
In 1968 Ishizaka and Johansson identified immunoglobulin E (IgE), which is a protein that is found in increased amounts in people with allergies. IgE is responsible for the allergic reaction that causes allergy symptoms.
The first, non-drowsy antihistamine came on the market in 1980, and it generally improved the quality of life for people with allergies.
Purified insect venom allergy shots were introduced in 1980 as well and have been shown to be more than 95% effective in preventing insect-sting anaphylaxis.
An exciting future ahead
Allergy shots are considered extremely safe and effective for the treatment of allergic rhinitis, allergic asthma, and stinging insect allergy in adults and children generally age five and older. Patients selected for immunotherapy should adhere to the medical treatment regimen precisely as ordered by their health care provider. Allergy shots cannot be given when a person with asthma is having increased asthma symptoms.
Research continues for treatments to control allergies and asthma, and it will be interesting to find what the next 100 years has in store!
Karen Gregory is a member of the American Association for Respiratory Care and resides in Oklahoma, where she serves as a respiratory therapist, advanced practice nurse, and certified asthma educator at the Oklahoma Allergy & Asthma Clinic in Oklahoma City.