Can you be more specific about what the rash looks like? How large is it? Is it scaly? Are there raised bumps? Does it itch? The more information we have the better we can assist you.
Based upon what you've shared though, since it is purple/brown, it does not sound like a candida infection. Candida is typically white or pink depending on where it is located externally. Perhaps you have a form of eczema.
Have you taken Antibiotics recently and/or are you diabetic?