A skin scratch test can be used if the results of the skin prick test are not clear. This involves
removing a small area of skin and then "rubbing" the allergen over the skin. That way, the
substances reach deeper layers of tissue than possible in the skin prick test, with the aim of
provoking a stronger reaction. The skin scrape test is similar, but only the outermost layer of skin is
removed.

In these tests, it’s not possible to regulate exactly how much of the allergen enters the skin and
tissue. They are also more likely to cause non-allergic skin irritation than the skin prick test is. So this
test is considered to be less reliable.