Sublingual immunotherapy for inhalant allergies deserves deeper consideration

Sublingual immunotherapy for the treatment of allergy symptoms caused by a wide variety of environmental inhalants has been effectively used in Europe.

It should be employed to further treatment of allergies in the United States, where allergic symptoms are largely undertreated, according to an invited article in the April 2009 issue of Otolaryngology-Head and Neck Surgery . A response to the article, published in the same journal issue, expresses cautious optimism, but calls for additional research.

Sublingual immunotherapy (SLIT) involves the administering of an allergen solution under the tongue, which in time reduces the patient's sensitivity to those allergens. The more prevalent alternative is subcutaneous immunotherapy, usually administered through an injection.

The authors of the invited article note that despite allergic symptoms contributing heavily to poor quality of life, high socioeconomic costs, and increased health issues, these syndromes remain underdiagnosed and undertreated. The authors attribute this to a public attitude that trivializes allergic conditions, along with patients' general dissatisfaction with the conventional pharmacy-based ways of treating allergic conditions. They conclude that the extensive implementation of SLIT treatment in Europe has proven to overcome these shortcomings in reaching patients, and the treatment is supported with significant literature documenting its efficacy, along with extensive clinical experience.

In a response to the invited article, AAO-HNSF Board of Directors member John H. Krouse, MD, PhD, recognizes the promising data associated with SLIT treatment, but urges caution until several issues can be addressed. Specifically, Dr. Krouse offers five areas of concern with SLIT treatment: patient selection; pattern of sensitization; dosing, preparation, and delivery; safety; and the financial cost of therapy. He concludes by noting the existence of a gap in allergy management in the United States, and the promise SLIT treatment holds, if carefully evaluated, in reaching these unaddressed segments of the population.

Allergy symptoms appear when the immune system reacts to an allergic substance that enters the body as though it is an unwelcomed invader. The immune system will produce special antibodies capable of recognizing the same allergen if it enters the body at a later time.

When an allergen reenters the body, the immune system rapidly recognizes it, causing a series of reactions. These reactions often involve tissue destruction, blood vessel dilation, and production of many inflammatory substances, including histamine. Histamine produces common allergy symptoms such as itchy, watery eyes, nasal and sinus congestion, headaches, sneezing, scratchy throat, hives, and shortness of breath, among others. Other less common symptoms are balance disturbances, skin irritations such as eczema, and even respiratory problems like asthma.