Hi, Thanks for your question, The scabs on your back and nape of neck are unlikely to indicate psoriasis, because the rashes which occur in psoriasis are most commonly found around the joints, legs, and trunk. Those rashes likely indicate a condition called nostalgia paresthetica. A condition associated with any disease of the spinal bones of the neck. Possibly, the rheumatoid arthritis you were diagnosed of may have neck involvement. This condition is only temporarily abated by prednisolone. The main treatment is by correcting the nerve impingement caused by the spinal disease and the rashes would subside and disappear. I therefore advise you revisit your doctor for a possible referral to an orthopaedic surgeon for evaluation and treatment. I hope I have answered your question. Best wishes.