Hello, I have a skin allergy named as dermatographic (also known as skin writing). Whenever I feel itchiness on my skin I stretch there and that portion becomes reddish and swollen after 2 - 3 mins and after 15-20 mins it becomes normal. Sometimes this itchiness spread in my whole body. I am facing this problem since 2 years. Kindly suggest any medicine for me. None of my family member is having this kind of disease. Or should I take any kind of blood test.