Acne and rash on back of my head

Hi!  I have had an itchy rash on the back of my head for the past 8 years.  It is reddish, mostly flat with some raised bumps (some become pimples).  There are areas of red that coalesce and thicker areas of skin.  I have tried washing with Selsun Blue shampoo before, and occasionally tried Clindamycin gel on my skin with little improvement.  Can anyone suggest a diagnosis and a cure?  I have included the picture below.

[chunkychen]

and btw, thanks for taking the time to suggest stuff!

[Dr_Aparna]

Hi,
Ringworm, an infection of the outer layer of the scalp and in the hair. It usually causes a rash made up of circular patches with raised, red edges that resemble worms. The rash spreads from these edges, often leaving the center clear, giving it a ring shape.
Topical antifungal drugs containing miconazole (Daktarin, Micatin & Monistat), clotrimazole (Canesten, Hydrozole), terbinafine (Lamisil), butenafine and tolnaftate (Tinactin), many available without a prescription, are used to clear up the infection. Pyrithione zinc, found in Head & Shoulders shampoo, is a very effective treatment for ringworm on the scalp and can be used as a body wash to assist in overall treatment.
If it does not improve iy could also be eczema or psoriasis of scalp.
ref:http://en.wikipedia.org/wiki/Ringworm

[chunkychen]

Thanks for the advice!!  I'll definitely take it up :)