Suggest Remedy For Itchy Rash On Pubic Line Spreading To Hips And Legs

hiya . over the past few days iv developed a rash above my pubic line , it started as just itching but now its a rash and its spred to my hips . lower bum and legs and now inbetween my testicles but not actually on my genitails . now i have tryed anti histamina tablet and they did nothing . i have also tryed hydrocortisone cream and no joy . can you help