Investigation of asthma
An investigation of suspected asthma, includes
allergy testing (skin test and possible blood test),
evaluation of the lung function and often an airway provocation (see below).
Skin testing involves placing drops of a number of common allergens onto the skin and then make a small prick through the drop into the superficial layer of the skin. If the skin reacts with swelling and redness, allergy to substances is indicated.
The
blood test is analysed in laboratories and also shows which substances there is an allergy to.
The
lung function is for example measured with a peak-flow meter. The lung function is often measured both before and after inhaling an air passage widening drug. An improved lung function indicates that there is a narrowing of the air passages and that this can be treated medically.
Air way provocation means inhaling an irritant (e.g. histamine or methacholine) or sometimes the substance one is presumed being allergic to. The lung function is then measured to see how strong a contraction of the air passages is achieved. The examination indicates how sensitive the air passages are.
