I have had itchy skin for quite some time. When I scratch, I get raised welts that aren't red. Sometimes they are parallel lines. Stress?

Dermographism. Twitchy mast cells. A physical urticaria, not an allergy. Skin reacts to stroking. A topical steroid, probably prescription strength, to reduce itch will reduce scratching, thus reduce welting. Benadryl (diphenhydramine) and Atarax are very sedating and therefor appropriate only at bedtime. The best antihistamine for this is usually Zyrtec [cetirizine] which is sometimes used at 2 or 3 a day if 1 is not effective.
Dermatographism. Your skin symptoms of itching or hyperreactivity can be due to allergy to something internal or external and may even be due to chronic stress. Antihistamines like Benadryl (diphenhydramine) or Claritin may help. Atarax has been helpful also. See an allergist if symptoms persist although sometimes a cause cannot be found.