Askipedia does not encourage or support any illegal drug use in anyway at all.
Anyone can be allergic to anything essentially. An allergy is your body deciding that it does not like a certain substance. When you have an allergic reaction to something your body is causing the damage to itself, the foreign substance is really doing you no harm. Your body is hypersensitive about coming into contact with the substance you're allergic too. So it tries too hard to fight off the invader, the result is an allergic reaction. The way your body fights the substance is by activating its mast cells, these cells produce histamines. Histamines attack the foreign substance until it is gone. This battle can produce a runny nose, or can cause death or coma. These histamines are also what cause mosquito bites to itch.
Testing for allergies are usually done with a skin test, and marijuana is no different, although you'll be hard pressed to find a doctor to administer that particular test. While there is no guarantee that any home test is safe, it is unlikely that rubbing a little bit of marijuana on your skin will be very harmful. If you develop a rash or significant itchiness you may be allergic.
Just say no to drugs.
http://www.theantidrug.com/drug_info/drug_info_kids_sayno.asp
