About This Condition
Psoriasis is a common, poorly understood condition that affects primarily the skin but may also affect nails. A related condition, psoriatic arthritis, affects joints.
The fact that some people with psoriasis improve while taking prescription drugs that interfere with the immune system suggests that the disease might result from a derangement of the immune system. A dermatologist should be consulted to confirm the diagnosis of psoriasis.
The hallmark symptom of psoriasis is well-defined, red patches of skin covered by a silvery, flaky surface that has pinpoint spots of bleeding underneath if scraped. The patches typically appear during periodic flare-ups and are in the same area on both sides of the body. In some people with psoriasis, the fingernails and toenails may have white-colored pits, lengthwise ridges down the nail, or yellowish spots, or may be thickened or may separate at the cut end.