The Apley scratch test can tell you a lot about your mobility in relation to aging well. Here's how to do it and what your results mean. Training your shoulder mobility may not seem as exciting as ...

The one doctors use most often is called a scratch test. A doctor or nurse will put a tiny drop of an allergen on your skin, usually on the inside of your arm or on your back.

If you're having a scratch or skin prick test, your doctor or nurse will look at the skin on your forearm or back and clean it with alcohol. They'll mark and label areas on your skin with a pen.

On Friday, May 10, the Kissing Booth alum, 24, shared a social media photo of an allergy test that she had done. Her entire back was covered in markings made of orange ink.