Histamine challenge test

Is a test that measures airway spasm and narrowing under controlled conditions. You will be asked to inhale an irritable and harmless substance (histamine or methacholine causing airway inflammation or mannitol causing dryness) to assess the reaction of the airway and its diameter.


It is not necessary to be sober. You are allowed to eat and drink before presenting. To ensure successful testing it is necessary to stop taking certain medications. You will get a list indicating which drugs to discontinue temporarily. This list for example contains bronchodilator drugs, anti - allergy medications and / or corticosteroids (inhaled). Avoid extreme stress before doing the test as it may have adverse effects on the result.

The exam

Relaxed sitting in a chair you will be asked to take a mouthpiece in the mouth which is connected to a measuring device. Through the mouthpiece you can breathe freely. Then the lab technician places a clip on the nose to ensure only breathing through the mouth happens. At the beginning of the test, the technician will ask you to inhale deeply and exhale very hard a couple of times. Next you will be asked to inhale an ascending dose of nebulized histamine intermittently. After inhaling the histamine you may feel some suffocation (narrowing of the airways) or start to cough. The lab technician will immediately administer a medication that instantly makes your airways more spacious. The feeling of suffocation is then rapidly reduced. The exam lasts approximately between half an hour and an hour and a half.


After the test, you can go home. You can continue with your daily life as usual. You may experience mild sore throat, irritating cough and / or hoarseness. This usually goes away by itself. The test is not risky, but it is strenuous because of the many times you have to in and exhale.