I am Dr. Ghazala Abdalgader, currently I am studying Diploma in Clinical dermatology course at Cardiff university, UK.
I have to do a dessertation on DLE, and I have no idea how to write it, so I will be very gratefull if you could help me .

I am looking forward to hear from you in the near future.

Well if you really are already a doctor, a simple dissertation (http://dictionary.reference.com/search?q=dissertation) should be a walk in the park.
You obviously have net access so its time to use Google.

10 seconds on Google and I found this (http://www.google.com/search?hl=en&q=discoid+lupus+erythematosus&btnG=Google+Search). Since you already are a doctor, you should be very familiar with the dissertation process.