What Causes Severe Dandruff On Head And Face With White Patches?

Hi, may I answer your health queries right now ? Please type your query here... I have severe dandruff on my head and now it has spreaded on my face ,eye brows &beard.I have rash on my chest and back. I am also getting white patches on my face and this is really making me worrying.Is it because of dandruff that i am getting white patches? Please help me to get rid of them