I Have Ringworm Infection(Tinea Corposis). This Is The 4th Time

I have ringworm infection(Tinea Corposis). This is the 4th time in the past 3 years that the infection has reoccurred. Affected parts are groin region and buttocks. My doctor had adviced me to use the following mediation:
1) Itraconazole 200mg for 8 days
2) Zoderm E cream for a Month
After one month he adviced me to use Fluconazole dusting powder and a Keto soap(twice a week). But after 1 and 1/2 months, things haven't improved much. Help!