Suggest Treatment For Scrotal Dermatitis

Hi, I have scrotal dermatitis from last 4-5 years. But it was not problem for me all round the year. Specially the summer months I am in serious trouble. At first I used Cotrimazole ointment and it was effective. But later it was not cured all the time. The I used to prefer Whitefield Ointment. It reduces the irritation for 5-6 hours, but again the same crisis evolve. Now what should I need to use ?
I am from Bangladesh.