You must be suffering from urticaria
There is a long list of causes of urticaria - infection, infestation, intake of specific food item or drug etc. Many a times it is idiopathic i.e. we do not find any cause.
It may be autoimmune, which means some autoantibodies have formed.
If your doctor has put you on Dynolap, then do one thing - take the medicine daily irrespective of the rash
appearing or not. Second thing is that take it at a fixed time.
Dr. Ajit Singh Kulhari
MD - Skin & VD