Skin prick testing

This testing is performed to confirm the presence (in the skin tissue) of specific IgE that is responsible for immediate allergic reactions. The test involves putting a drop of allergen extract on the skin, usually on the forearm, and then pricking the skin through the drop with the tip of a lancet.

Two control solutions (one positive, one negative) are used at the same time to make sure that the test has worked correctly. If there is a positive response, the skin will become red and swollen within minutes, like a nettle sting. The wheal has a raised edge that slowly expands to reach its maximum size in about 15 minutes, after which it goes down. Skin prick tests should only be performed and interpreted by trained personnel in appropriate facilities.

Antihistamine medicines can prevent the normal response to a prick test. Long-acting (non-drowsy) antihistamines should be discontinued five days before the test and short-acting antihistamines (e.g. those in cough medicines, cold cures and some OTC sleeping tablets) should be discontinued 48 hours before the test. At least 15 per cent of people with a positive skin prick test do not develop symptoms on exposure to the relevant allergen.²

Management

Evidence-based guidance on the management of AR is available^1,2,4. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines1 probably represent the most comprehensive, evidence-based resource and a pocket-reference version is available.⁴ The ARIA guidelines are periodically updated. Many of the treatments for mild-moderate disease are available from pharmacies. Effective treatment can improve quality of life and reduce the risk of complications, such as loss of asthma control.