Thank you for answering my question, Dr. Kaur.
This makes sense, as I have had different outbreaks of much more unpleasant dermatographism during apparent allergic drug reactions. During these reactions, anywhere I had scratched in the night while asleep became very red streaks the next day that looked like lashes from a whip. I'll ask my doctor about cromoglicate, as you suggested for more serious outbreaks.
I didn't know that it could also present in the minor-annoyance form of patterns on the skin from pressure.
I seem to have many unexplained chronic skin symptoms, so perhaps they are mostly due to the same condition. Urticaria, angioedema, generalized pruritus w/o rash, occasional full-body rash with dermatographism, dyshidrotic eczema. Only the urticaria seems to respond to antihistamines.
This is due to dermatographism. Dermatographism can be caused by stress, tight or abrasive clothing, watches, glasses, energetic kissing, heat, cold, or anything that causes stress to the skin. In many cases it is merely a minor annoyance, but in some rare cases symptoms are severe enough to impact a patient's life.
It can be treated by antihistamines or cromoglicate and sometimes steroids, as they prevent the histamine from causing the reaction. As the underlying cause of dermographism is not known, it can last for many years without relief.
I hope it helps. Take care and please do keep us posted on how you are doing.