Dermatographia is a condition in which lightly scratching your skin causes raised, red lines where you’ve scratched. It’s not serious, but it can be uncomfortable. In dermatographia, the skin cells are overly sensitive to minor injury, such as scratching. Signs and symptoms of dermatographia include redness, itching and swelling similar to hives.
So she painlessly draw patterns and words on her skin, and photograph these. Unique, isn’t it?
(From Crooked Brains)