Chapped and sore fingertips

[Ssq51]

I have been diagnosed with psoriasis, specifically on my palms and a little under one arm.  My eyelids and lips were also very chapped.  I was prescribed some creams for both my palms and eyelids, etc. which seem to keep it down, providing I use it all the time.  My new problem is my fingertips on my left hand.  They are very raw and painful.  The pain is like very small paper cuts.  My nails on some of my fingers are also coming away from the nail beds.  Is this associated with psoriasis.  No creams ( and I have quite a few that have been prescribed) seem to help.  
Thank you.
SS

[Dr_Aparna]

Hi,
Psoriasis is a disorder which affects the skin and joints. It commonly causes red scaly patches to appear on the skin. The scaly patches caused by psoriasis, called psoriatic plaques, are areas of inflammation and excessive skin production. Skin rapidly accumulates at these sites and takes a silvery-white appearance.
Nail psoriasis  produces a variety of changes in the appearance of finger and toe nails. These changes include discolouring under the nail plate, pitting of the nails, lines going across the nails, thickening of the skin under the nail, and the loosening (onycholysis) and crumbling of the nail.
Bath solutions and moisturizers help soothe affected skin and reduce the dryness which accompanies the build-up of skin on psoriatic plaques.
Medicated creams and ointments applied directly to psoriatic plaques can help reduce inflammation, remove built-up scale, reduce skin turn over, and clear affected skin of plaques. Ointment and creams containing coal tar, dithranol (anthralin), corticosteroids like desoximetasone (Topicort), vitamin D3 analogues (for example, calcipotriol), and retinoids are routinely used.
ref:http://en.wikipedia.org/wiki/Psoriasis
Once the condition is under control then some of these manifestations can be reversed.