[header] How to know if you have jock itch [title] Recognize the symptoms. [step] It is a red rash that covers the inside of your upper thigh, skin on your genitals, and may go as far back between your buttocks as your anus. [substeps] The rash will likely itch and burn. 
If it spreads to your anus, you may also have anal itching. It may look flaky with a raised, swollen appearance.