sometimes my hair bang will rub up against it and welts would form. If i physically get hit, pinched, scratched, slapped, the area would welt and redden.Sometimes i could do nothing to irritate the skin and i would find welts. First what would happen is i would get itchy and the irritated area would get hot (not burning sensation), red, sometimes i would feel a little throbbing, then the skin would swell.It would last about 5-30 mins, it depends on how severe the irritation is. There is no pain just itchiness and warm feeling. I found articles about urticaria
You seem to be having dermographism. Dermographism is a normal physiological response of the skin. The term literally means writing on the skin. Firm stroking of the skin produces an initial red line (capillary dilatation
), followed by an axon-reflex flare with broadening erythema (arteriolar dilatation) and the formation of a linear wheal (transudation of fluid/edema) termed the triple response of Lewis.
The exact mechanism of dermographism remains uncertain. Trauma may release an antigen that interacts with the membrane-bound immunoglobulin E of mast cells, which release inflammatory mediators, particularly histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin
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 pls do keep me posted on how you are doing or in case you have any additional doubts. Kind regards.