I've been on Ritalin 20mg 2 x per day and 10mg 1x per( 50mg) for almost 5 yrs now. I was diagnosed with adult ADHD about 8 yrs ago but didn't start medication until my ADHD was starting to really effect my job, ability to concentrate, get organized and I then agreed with my doctor to start taking the Ritalin, brand not generic. I only started taking the generic for of Ritalin20mg er ( methylphenidate20mg sa) I've recently noticed the rash only happens with a specific brand, the metadate 20mg er. Has anyone had this problem? Any feedback would really be helpful as I don't know if it has happened to anyone else or if it could be something else? Thanks.