hello this is the exact same thing I have... in september of 2010 i had to get rectal surgery that wasnt succesfull... well i had alot of problems after that... well one day I noticed a cyst close to where i had my surgery on the outer side og my butt... well right after that i started getting a really bad rash on the front of my legs... Well now it has spread to my arms..ive been to so many doctors and taken so many steriods and antibiotics and nothing cured it.. well im seeing a new surgen and he figured out what was causing the rashes and the boil on my side.... I have MRSA... which is a bacteria that can be very dangerous. there is many different ways a staph infection can start and mine was bacteria either getting into my open wound after my surgery, a cut,  dry skin, or even cutting your legs while shaving and you used the same razor as a family member... I just thought i was allergic to something but i was wrong... MRSA can often be misdiagnosed for a heat rash, razor burn, spider bites, ingrown hairs, or even pimples.... im only 18 and i always have the chance of it coming back since i have already had it.... But my symptoms started just like everyone posting!!!! so good luck!