If you are suffering from minor topical diseases that are fungal in nature, there is an easy way to steer clear of them or prevent them from worsening. Use anti-dandruff shampoos.
Anti-Dandruff shampoos mostly have Zinc Pyrithion or Selenium Sulfide in the active contents and both of these components in the shampoo help you from fungal infections in the hair, dandruff being one of them.
For a fungal infection on the skin tinea versicolor, midly wash it with the shampoo regularly everyday and you will see improvement soon. Alternatively you can also go for coconut oil since it is a natural antifungal product.
Smear a layer of coconut oil thrice a day over the affected area and observe results as fast as a couple of days.