A patient came to me with the complaint of severe itching on his buttocks and under thighs, he has had oral medication of ketoconazole, itraconazole and fluconazole tab at various times in the past 4 months. He has also been applying ketoconazole and betamethasone ointment and since then on and off. The infection has flared again 15 days back.

What should be the correct treatment for the fungus and how long should it be sustained?