[7] Potential side effects related to subcutaneous immunotherapy treatment for asthma and allergic rhinoconjunctivitis include mild or moderate skin or respiratory reactions.
[8] Discovered by Leonard Noon and John Freeman in 1911, allergen immunotherapy is the only medicine known to tackle not only the symptoms but also the causes of respiratory allergies.
[10] Subcutaneous immunotherapy (SCIT), also known as allergy shots, is the historical route of administration and consists of injections of allergen extract, which must be performed by a medical professional.
[14] It is possible, but rare (1/2.5 million), that people undergoing subcutaneous allergen immunotherapy may experience a fatal anaphylactic event.
[15] Sublingual immunotherapy involves putting drops or a tablet of allergen extracts under the tongue, which are then absorbed through the lining of the mouth.
[16] They include swelling of the mouth, tongue or lip, throat irritation, nausea, abdominal pain, vomiting, diarrhea, heartburn, and uvular edema.
[16] Oral immunotherapy (OIT) involves feeding an allergic individual increasing amounts of a food allergen in order to raise the threshold which triggers a reaction.
[19] Long-term, many study participants still experienced mild allergic reactions or needed to regularly consume the allergen to maintain desensitivity.
[22] In January 2020, the FDA approved Palforzia for mitigating "allergic reactions, including anaphylaxis, that may occur with accidental exposure to peanuts.
[26] Despite this, multiple clinical trials and systematic reviews have demonstrated that ILIT is safe and effective in reducing symptoms of allergic rhinitis and medication use.
[30][31] Patients who undergo acute desensitization commonly experience mild allergic side effects such as itching, hives, and wheezing.
[31] Transdermal immunotherapy (TDIT) involves skin-induced suppression via epicutaneous (EC) application of an antigen in order to raise the threshold which triggers a reaction.
Early effects of allergen immunotherapy primarily involve suppression of mast cells and basophils, which increases the threshold of anaphylaxis.
[citation needed] The British physicians Noon and Freeman were the first researchers to test pollen allergen immunotherapy in humans.
Noon and Freeman, researchers at the Department of Therapeutic Inoculation at St. Mary's Hospital in London, published their findings in The Lancet in 1911.
[36][37][non-primary source needed][failed verification] Building on the observations of his predecessors Bostock, Blackley and Dunbar, Noon noted that people with hay fever "sometimes become cured" and that this was possibly because they "have had the good fortune to develop an active immunity against the toxin."
[39] In 2014, the FDA approved a once-daily sublingual tablet containing allergen extracts for the treatment of "hay fever" (allergic rhinitis with or without conjunctivitis).
[41] Subcutaneous immunotherapy is both approved and regulated by the American Food and Drug Administration (FDA) and the European Medicinal Agency (EMEA).
[42] The FDA currently allows individual allergists to create the formula for each dosage, whereas the EMEA requires treatment extracts to be prepared at manufacturing sites.
It is seen where it can be covered by insurance and offer a more permanent solution than antihistamines or nasal steroids that treat symptoms, not the body's reaction.
Subcutaneous allergen immunotherapy, according to the scientific community, is an effective solution to allergies due to numerous positive studies.
[1] As of 2011[update], OIT was under investigation as a treatment for a variety of common food allergies including peanuts, milk, and eggs.
[35] Another approach to improving oral immunotherapy is to change the immune environment to prevent TH2 cells from responding to the allergens during treatment.
While it is possible that omalizumab, FAHF-2 or other immunomodulatory agents alone might be able to treat dangerous allergies, combining these with OIT may be more effective and synergistic, warranting further investigation.