Hello,
Welcome to the ehealthforum and I am really glad to help you out.
Unfortunately the picture could not be opened from the link But if the patch has been present for more than an year without any change in size and shape, it is best to get it biopsied from a dermatologist to confirm the diagnosis. This patch can be due to eczema, psoriasis or any other chronic disease. Treatment is diagnosis specific, so get it biopsied.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.