In mechanics, a force is that which causes a change in velocity or, if you prefer, that which causes an acceleration. When more than one force acts on an object it is the net force that is important. Since force is a vector quantity, use geometry instead of arithmetic when combining forces.
Quick Answer. A crawling sensation felt on the skin may be caused by a condition called morgellons, according to WebMD. Common symptoms of morgellons include feeling like bugs are crawling on the skin, burning, itching and stinging sensations. In some cases skin sores may appear as well.
The most fundamental of all causes for dermatographism is the application of friction or pressure to the skin. This is not the underlying source of the problem, but it is what triggers the appearance of the dermatographism symptoms. It is speculated that pressure or friction on the skin causes the release of inflammatory mediators. Visit our pictures of skin rashes page for more information.