This condition need to be treated with medicated shampoos containing ketoconazole 2% and salicylic acid content.
It should be applied for 5 mins on scalp and than rinsed off. Twice a week application will help
If it is excessive oral ketoconazole tablets also help
Next Steps
Best would be to visit the dermatologist near you and get yourself evaluated.
Health Tips
Donot keep the hair wet for long after wash and donot oil wet hair.