What are the basic differences in symptoms and clinical menifestations between psoriatic arthritis and rheumatoid arthritis?

Less symetrical : Psoriatic arthritis comes in several forms. The main difference between RA and the type of psoriatic arthritis that is closest to rheumatoid is that psoriatic is less symetrical. Psoriatic is also associated with nail changes, more tendinitis problems, and psoriasis. It is very rare for RA to affect DIP (joints at end of finger). Psoriatic will affect these. There are many other small diff.