AlT: A cure to respiratory allergies
What is AIT?
AIT the full form of which is allergen immunotherapy has been wonder treatment option for patients with allergies. AIT also known as desensitisation or hypo-sensitisation is a therapeutic treatment where the allergen is given in larger doses in order to reduce the sensitivity of the patient towards the allergen. In this way we are able to modify the body’s immune response to allergen. This therapy has been largely useful to the patients suffering from allergic rhinitis, asthma, allergic conjunctivitis and stinging insect bite allergies. It is not useful for individuals suffering with food allergies, as in those the only option for treatment remains simply avoiding consumption of the food that they are allergic to. Statistical analysis obtained from various past scientific studies in similar field reveal the safety and efficacy of such AIT skin injections (allergic shots) in treating allergic rhinitis in children, the benefits of which last for several years after the treatment is stopped.
History- Who discovered?
In 1911, Leonard Noon and John Freeman formalised the effect of of allergen immunotherapy as the only medicine useful for treating respiratory allergies. However, focus has also been laid on detailed diagnosis and identification of allergens involved.
Routes of administration.
also known as allergy shots is one of oldest method of administering the drug and consists of allergen extract. Certain guidelines which help in proper administration of the drug have been laid and Comprises of 2 phases:
· Build-up phase - involves weekly injections the dose of which is increased about one to two times per week. The duration of phase is usually of 3-6 months.
· Maintenance phase - involves monthly injections and is continued for a period of 3-5 years.
Ones the effective dose is attained in the build-up phase, only then the maintenance phase is initiated. The effective dose will depend on how the patient responds every time the dose is increased.
Involves drops or a tablet of allergen extract under the tongue. Mainly observed to be effective in rhino-conjunctivitis and asthma.
Dose via this route is given in multiple doses over a 12 week period. Except of the first dose which is administered by the clinician, all subsequent doses can be self-administered and therefore the patient compliance with this method is better.this method is currently most comercialized in European and South American countries. However in the US, these allergen drops are yet to receive FDA approval, even though off-label prescriptions is becoming common.
Other routes which less commonly used are oral and transdermal.
Currently the most supported approach has been subcutaneous administration of AIT which has been approved by maximum organisations like World allergy Organization, Canadian Society of allergy and immunology, European academy of Allergy and clinical Immunology, and the American Academy of Allergy, Asthma and Immunology. Subcutaneous immunotherapy is both regulated and approved by FDA.