Physical Urticaria: Maps that appear on the skin

Physical Urticaria is one type of condition that can cause rashes to appear randomly on the skin. It is not yet very clear why it makes rashes appear on the skin, although the nearest explanation so far is that it is due to the release of histamine and other chemicals when your skin reacts to it.

In general, urticaria is a skin condition that causes rashes, also known as hives or weals, to appear on the skin. Physical urticaria distinguishes itself from the other type of urticaria in that this one is brought about when the skin is physically stimulated. This is in contrast to others wherein the stimulation comes from allergies, skin contacts to chemicals, and possibly reaction to viral infection.

Physical stimulation refers to actions that physically trigger the skin to react, such as when applying pressure on the skin (handling tools, sitting on a rough surface, etc.). Another more common cause is when there is a sudden increase in your body temperature, which on the other hand is caused by external factors like eating spicy food, exercise, prolong exposure to sunlight, or even cold temperature.

Physical urticaria can be further classified into different types. These can be dermographism, cholinergic urticaria, cold urticaria, delayed pressure urticaria, and solar urticaria. Each one is associated with a different physical stimulation that acts as the triggering mechanism to the rashes to appear.

A more detailed explanation, as well as treatment procedures, can be read in a wonderful guide found in this site.