Number sign. Not to be confused with the Chinese character äº, the sharp sign (â¯), the viewdata square (â), the numero sign (â), the equal and parallel to symbol (â) or the game Tic-tac-toe's grid. The symbol # is most commonly known as the number sign, hash, or pound sign.
The poison ivy rash is not contagious. When a person touches the poison ivy leaf, a substance on the surface of the leaf (a resin) rubs off. Over the next 48 to 72 hours the skin reacts to the resin by becoming red and developing bumps and blisters at and around the site where the resin was.
1 The reason: They both cause contact dermatitis â skin becomes inflamed from an irritant or a substance that produces an allergic reaction. 2  In the case of poison oak, poison ivy, and poison sumac, itâs the chemical urushiol that causes the reaction. Treating Poison Oak Rash Symptoms of and treatment for poison oak are the same as for poison ivy. 2  The reason: They both cause contact dermatitis â skin becomes inflamed from an irritant or a substance that produces an allergic reaction.