What you are describing is a phenomenon called dermatographia, or dermatographic urticaria. The symptoms of dermatographia are hives
(also called urticaria) whenever the skin is scratched or rubbed. In some cases, pictures and words can even be drawn into the skin and they appear a short time later in the form of hives (hence the name dermatographia). The hives are caused by the release of histamine into the skin. The cells that release this histamine are called mast cells. The reaction is not an allergy per se, but it does represent a very active side of the immune system that reacts to allergens. Thus patients with this syndrome tend to be people with some very active allergies. Most of the time, dermatographia occurs for unknown reasons. In rare cases, it can represent an underlying disorder of the immune system.
I suggest that you schedule an appointment with an allergy specialist. He or she can take a more detailed history of your symptoms and perform a thorough physical exam. The allergist will likely want to get some baseline laboratory tests and perhaps perform some basic allergy testing. These specialists have medications such as newer shots and medications with few side effects which can calm down these symptoms. Good luck.