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Hot Clues To A Cool Nose

July 08, 2004

In an attack of hay fever, the temperature of the nose rises. Effective medication prevents this too. An infrared camera provides non-contact images of the changes. Researchers can use these images to determine how reliable and effective anti-allergic agents are.

When summer comes, it brings with it severe sneezing attacks and itching eyes. People who suffer from hay fever can tell you all about how sometimes a pack of tissues does not even last long enough for a short Sunday stroll. The alternatives are to sit at home with all the windows tightly shut or to inhibit the body's allergic reaction by using medication. There is a range of drops, tablets and sprays available, and new types of medication are being tested. Research scientists at the Fraunhofer Institute for Toxicology and Experimental Medicine ITEM in Hanover are working on an elegant method for testing the effect of anti-allergic agents.

The temperature of the nose is an indicator of hay fever and its effective treatment. Pollen and other allergens such as airborne house dust affect allergy sufferers in that the body's own messenger substance histamine is excessively and often suddenly released. The tissue hormone dilates the blood vessels in the nasal mucous membrane. "The flow of blood through the nose increases and as a result radiates more heat," explains Michael Larbig, head of the ITEM test laboratory. "We register this using an infrared camera." A software system translates the microchip signals into images whose color graduations reflect the temperature of the skin. If a hay fever remedy works, the color shift is less pronounced than otherwise. This phenomenon can be observed non-invasively and very sensitively for hours on end by means of thermography. Because this system is contactless, it can replace or supplement other methods in which, for example, secretions have to be weighed or the flow of air through the nose has to be measured.

In an initial study conducted on people who do not suffer from hay fever, Larbig and his colleagues, working in cooperation with the Belgian company UCB Pharma S. A. based in Braine-I'Alleud, compared the effect of two already licensed antihistamines. They gave the test persons the recommended single dose of the medication concerned and allowed two hours to pass for it to take effect. They then simulated an allergic attack by spraying histamine in the test subjects' noses. One of the two products reduced the increase in temperature of the nose immediately after the contact time. In a follow-up study the research scientists have now tested a third remedy, and the results were presented at the EAACI Congress (European Academy of Allergology and Clinical Immunology) in Amsterdam just the other day. Further studies in which the scientists will use allergy-sufferers as test subjects are already planned.

Fraunhofer-Gesellschaft