The American Heritage® Dictionary of the English Language defines Psoriasis as:
"A noncontagious inflammatory skin disease characterized by recurring reddish patches covered with silvery scales."
Take a look at the various chapter previews to find out more information about specific areas of your scalp situation.
And for a full discussion of Scalp Disorders, we recommend purchasing a copy of Sylvia Sage's eBook - "How to Overcome Dandruff and Other Scalp Disorders".