Skin Prick Test (SPT)

Skin Prick Tests (SPTs) or scratch tests are quick ways of testing specific allergens to identify what one is allergic to. Some allergens include pollen, fungal substances, mites, and specific foods.

The Skin Prick Test searches for a specific antibody known as Immunoglobulin E (IgE). Let's say that you are allergic to dust mites. Your body would produce IgE to fight that particular dust mite protein.

Hence, these antibodies would coat the surface of mast cells. Mast cells are large cells found in the connective tissue, that are released upon the arrival of allergens.

Once the allergen is pricked into the skin, the allergen binds to the dust mite specific IgE antibodies. Then, the mast cell releases its contents.

The process in which a red, itchy bump forms is known as the Triple Response of Lewis. These are the three components of that process:

1. Dilation:is the process in which the capillaries expand, and therefore cause a red spot to form.
2. Flare:As the nearby blood vessels respond by expanding, a flush and increased redness surrounds the initial site of inflammation.
3. Wheal:Histamine makes the blood vessel walls slightly porous, blood leaks causing puffiness in the tissue.

The larger the bump, the more sensitive you are to the allergen.

The Skin Prick Test takes less than an hour, is easy and painless, and results are visible in 30 minutes.

What Is SLIT?

Sublingual Immunotherapy aims to reduce your allergic response to specific triggers. Typical treatment for allergies decreases symptoms. SLIT works to reduce the actual cause of the allergy. The overall aim for SLIT is to reach a dose where the allergen can be tolerated without consequence due to changes to the immunological system.

SLIT is performed by having an individual place drops of allergens under their tongue each day. Dendritic cells that capture allergen extract are present under the tongue and act as powerful antigen presenting cells. These cells then migrate to nearby lymph nodes and enhance the development of Regulatory T-cells. The aforementioned actions cause:

• Immune Deviation - The shift in response from a Th2 (allergic) response to a Th1 (non-allergic) response.
• Antibody Class Switching - The shift in which the Th2 and Th1 cells produce blocking antibodies of the IgG4 subclass which then binds the allergen and inhibits mast cell degranulation.

Your immune system calms down and stops hyper-reacting to your allergies.

SLIT is broken down into an initial build up period (1-2 years) and a maintenance period (1 year). When you take SLIT for 2-3 years, you build up a more stable tolerance to the allergen.

SLIT can be performed at home and is both painless and safe, are some of the reasons for its high success rates. SLIT helps you to overcome your allergies.