Saturday 01/20/2007

Innovations in Allergen Immunotherapy

Allergen immunotherapy has been utilized for almost 100 years to treat allergic rhinitis (hay fever). New developments using well-controlled studies within the past several years have shown other unique properties of high-dose immunotherapy as compared to the alternative of symptomatic treatment with medication. The goals of immunotherapy are to significantly reduce symptoms and complications and the need for other treatment (medication) of the condition for which it is used.

 Listed  are the methods that are currently being used by certain practitioners and their effectiveness.

I. Standard High-Dose Immunotherapy (Sub-Cutaneous ImmunoTherapy or "SCIT")

Utilized by trained pediatric or internal medicine allergists.

Positive properties determined by well-controlled studies:
1. Effective treatment for allergic rhinitis and bronchial asthma.
2. Effective doses established for many major allergens.
3. New insight gained behind the mechanisms of immunotherapy.
4. Immunotherapy can reduce the development of additional sensitivities in those with only one sensitivity.
5. Immunotherapy can reduce the likelihood of development of asthma in children with allergic rhinitis.
6. Benefits may persist for years after discontinuation of treatment.

Negative effects or risks of immunotherapy:
1. Local reactions. (Annoying and sometimes painful, but not dangerous).
2. Systemic reactions. (Occur at about a 2% rate, requires monitoring and treatment by a physician).
3. Fatal reactions. (One fatal reaction in every 2.5 million injections. There are no totally safe treatments of any type)

This form of treatment is the only method of "disease modifying' and is limited only by practical limitations of safety and inconvenience, but is well worth the effort for properly selected patients.

II. Low-dose SubCutaneous ImmunoTherapy "SCIT"

Utilized by otolaryngologists, some primary care physicians, and other health care providers

Low-dose immunotherapy has been utilized for many years by some practitioners. However, when compared to high-dose immunotherapy and placebo (plain water), it is ineffective. Some practitioners, primarily otolaryngologists and some primary care physicians, continue to utilize this form of immunotherapy because of perceived safety (less systemic reactions and convenience since these shot are often given at home ). Systemic reactions, however, may occur despite the very low concentration of antigens and the patients themselves must treat these reactions.

Other practitioners utilize low-dose immunotherapy and administer airborne allergens, foods, and chemicals with a "Titration-Neutralization" technique in which they claim the ability to detect doses that will trigger symptoms and then doses that neutralize symptoms. This form of immunotheray has been discredited by controlled studies that fail to show reproducibility and effectiveness. 

III. Sub-Lingual ImmunoTherapy or "SLIT"

Low-dose SLIT therapy

Utilized by otolaryngologists, some primary care and other health care providers

This type of immunotherapy has been utilized by non-allergist, primarily otolaryngologist (surgeons), in very low doses for years despite controlled studies showing this form of treatment to be no more effective than placebo (plain water). This has been utilized to treat food allergy and chemical sensitivity, as well, without any controlled studies to show effectiveness.  

High-dose SLIT therapy

High-dose sub-linqual immunotherapy is undergoing intense research at this time to further define it's role in treatment of allergic patients.  It appears to be about 1/2 as effective as subcutaneous immunotherapy in the first year. Effectiveness increases with continued use. It also has other attributes of subcutaneous immunotherapy including prevention of new sensitization, prevention of progression from rhinitis to asthma, and continuing effectiveness for years after discontinuation. It appears to be safer than subcutaneous treatment and therefore may be used by the patient at home

The problems with SLIT therapy is dosing. Only very high doses have been shown to be clearly effective. The volumes that would be required becomes cost prohibitive, if multiple allergens needed to be used.

The place for this type of treatment would be with single season allergic individuals or those with only one or two perennial allergens (Mite or animal sensitivity).

Other forms and methods of immunotheapy are currently undergoing scientific evaluation but are some years before commercial use.

Whichever form of immunotherapy prevails, success depends upon accurate diagnosis in which histories are confirmed by valid testing. Patient monitoring to assure the goals of immunotherapy are met is the responsibility of physicians trained in allergy and immunology. These responsibilities cannot be delegated to allied health care providers.(Nurses and medical assistents)



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