Skin allergy test

Skin allergy test

Skin allergy testing is a method for medical diagnosis of allergies that attempts to provoke a small, controlled, allergic response. A microscopic amount of an allergen is introduced to a patient's skin by various means:

* by pricking the skin with a needle or pin containing a small amount of the allergen ('Prick Testing' or 'Scratch Testing')
* by applying a patch to the skin, where the patch contains the allergen.

If an immuno-response is seen in the form of a rash, hives, urticaria or (worse) anaphylaxis it can be concluded that the patient has a hypersensitivity (or allergy) to that allergen. Further testing can be done to identify the particular allergen.

The "scratch test" as it's called, is still very commonly used as an allergen test. A similar test involving injecting the allergen is also used, but is not quite as common due to increased likelihood of infection and general ineffectiveness by comparison.

Skin end point titration (SET) uses intradermal injection of allergens at increasing concentrations to measure allergic response. [MeshName|Skin+Test+End-Point+Titration] To prevent a severe allergic reaction, the test is started with a very dilute solution. After 10 minutes, the injection site is measured to look for growth of wheal, a small swelling of the skin. Two millimeters of growth in 10 minutes is considered positive. If 2mm of growth is noted, then a second injection at a higher concentration is given to confirm the response. The end point is the concentration of antigen that causes an increase in the size of the wheal followed by confirmatory whealing. If the wheal grows larger than 13mm, then no further injection are given since this is considered a major reaction.

ee also

* Basophil activation
* Allergies
* Hypersensitivity
* Dermatitis
* Anaphylaxis
* Patch test (medicine)

References

External links

* [http://www.allergy.org.uk/ The British Institute for Allergies]
* [http://www.dermatology.co.uk/allergytesting/patchtesting/article/article.asp?ArticleID=747 Skin Allergy Patch Testing]
* [http://www.dermnetnz.org/procedures/patch-tests.html Skin Patches (Allergy Testing)]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Skin prick test — A test of IgE related allergy involving pricking through the suspect allergen into the epidermis of the skin and observing for an immediate hypersensitivity response. This includes: itching, erythema, weal and flare response. It is a diagnostic… …   Wikipedia

  • Allergy — Classification and external resources Hives are a common allergic symptom. ICD 10 T78.4 …   Wikipedia

  • skin test — noun any test to determine immunity or sensitivity to a disease by introducing small amounts on or into the skin • Hypernyms: ↑diagnostic test, ↑diagnostic assay • Hyponyms: ↑Dick test, ↑patch test, ↑Schick test, ↑scratch test, ↑ …   Useful english dictionary

  • RAST test — A RAST test (short for radioallergosorbent test) is a blood test used to determine what a person is allergic to. This is different from a skin allergy test, which determines allergy by the reaction of a person s skin to different substances. For… …   Wikipedia

  • The Alcat Test — was developed as a screening test for adverse reactions to specific foods, food additives, pharmacoactive agents to food chemicals and food colorings. The ALCAT test is based on the accurate measurement of cells volume and counting of the… …   Wikipedia

  • Patch test (medicine) — A patch test is a method used to determine if a specific substance causes inflammation of the skin. It is often used to test for allergens.Any individual with suspected allergic contact dermatitis and/or atopic dermatitis needs patch testing. The …   Wikipedia

  • skin test — n. any test for detecting the presence of a disease or allergy from the reaction of the skin to a test substance …   English World dictionary

  • Coombs test — Diagnostics MeSH D003298 Coombs test (also known as Coombs test, antiglobulin test or AGT) refers to two clinical blood tests used in immunohematology and immunology. The t …   Wikipedia

  • Medical test — Intervention X ray of a hand. X rays are a common medical test. MeSH …   Wikipedia

  • Complement fixation test — Diagnostics MeSH D003168 The complement fixation test is an immunological medical test that can be used to detect the presence of either specific antibody or specific ant …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”