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Skin prick-tests

Skin prick-tests

For the most common allergies, including pollinosis, allergies to animal dander, dust mites, wasps and certain foods, diagnosis can be established by standard skin prick-tests.Additional skin tests are sometimes necessary in the form of intra-dermo-reaction (IDR) or specific tests (prepared directly from the offending allergen, i.e. fresh food, medicines).Patch tests are useful in the diagnosis of contact dermatitis (delayed reaction). 

Standard skin prick-test

Skin prick tests are performed on the forearm. This is the first of the tests necessary to determine an allergy. The extracts used are manufactured by specialized laboratories in the detection of allergies. The skin reaction occurs after about 20 minutes and can provide all the elements needed to define diagnosis (allergy or hypersensitivity).

A drop of allergen is deposited on the skin, which penetrates by using a very fine instrument (prick). The reactions occur in 20-30 minutes and range from a simple little redness, itching, to swelling and/or papulous spots. These reactions are reabsorbed by themselves after a little while.

The tests are well tolerated by children.

Specific skin prick-test

It is sometimes necessary to test with an extract prepared directly from the offending allergen: your own cat’s hair,  fresh food, medicine, etc. For instance, it is possible to be allergic to a particular cat, but not necessarily to all cats. It is therefore useful to practice this type of test in case of persistent discomfort when the standard tests have not yielded clear results.

Intro-Dermic-Reaction (IDR)

IDR enable to perform allergy tests with a larger amount of allergens, directly under the skin.

This is a small injection into the skin, a little more sensitive than skin prick-tests. The reaction time is identical to a skin prick-test (20 minutes).

Patch-Tests

When contact allergy (eczema) is suspected, for instance caused by an everyday product component (perfume, shampoo, laundry, etc.) but we have difficulty to establish which component is the cause, patch -tests are the only way to clarify the problem.

  • standard patch-tests will eliminate or incriminate most usual components favoring contact allergies
  • personal or specific patch-tests will test your own cosmetics or personal care products and ensure whether they are causing your symptoms.

Usually performed on the back, patches are usually left on for 2-3 days before reading, because the reactions occur more slowly than with prick-tests.  Standard patch-tests are ready to place. Specific patch-tests will simply require a drop of the product to be deposited on the skin, and are then covered with a protective dressing.

A first reading is performed around the 3rd day, when  dressing is removed, then a final reading is done on day 5. Skin reactions resulting from these tests clearly establish which components are responsible for the allergy.

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