Poriasis is a common chronic condition of the skin affecting about 7 million people in the United States. Psoriasis develops when the immune system sends faulty signals that tell skin cells to grow too quickly. Since the body does not shed these excess skin cells, the skin cells pile up on the surface of the skin, causing patches of psoriasis to appear.
Depending on the type of psoriasis a person has, the affected areas may have patches of raised, red skin with silvery scale, or it may look shiny and red or even have pustules. While psoriasis typically appears on the scalp, elbows, knees, lower legs and trunk, it can affect the fingernails and toenails, causing the nails to appear thick, discolored and irregular.
Most people who have nail psoriasis also have psoriasis affecting another part of the body. It is rare to have nail psoriasis without showing signs of psoriasis anywhere else.
Signs and Symptoms
The nail area is made up of several parts. If you have nail psoriasis, you may have some, or most, of the following symptoms.
Clear yellow-red nail discoloring that looks like a drop of blood or oil under the nail plate – This is often one of the first signs that you have nail psoriasis.
White patches on your nail plate – This is caused by a reaction of your cells to psoriasis.
Thickening of the skin under your nail – This can lead to loosening of the nail.
Lines going across the nails (from side to side) – This happens when your cells respond to psoriasis by becoming inflamed, causing the lines to appear.
Small pits in your nails – This affects the nail matrix area and develops when cells are lost from the nail’s surface.
Splinter hemorrhages (or the tiny black tip-to-cuticle lines) – This happens because the tiny blood vessels bleed between the nail and the skin under the nail plate.
Redness of the Lunula (the half-moon part at the top of the nail) – this happens when the bottom of nail plate has congested capillaries.
Loosening of the nail – Your nail may develop a white area where it is separated from the skin underneath your nail. It usually starts at the tip of the nail and extends toward the root. If this happens, the nail bed (skin under your nail) could become infected.
Crumbling of the nail – Also called nail plate crumbling at the nail bed or nail matrix. This happens when the nail weakens because the underlying structures are not healthy.
Arthritis of your fingers with nail changes: The nails are affected in about 53%-86% of people who have psoriatic arthritis.
Nail psoriasis can also be accompanied inflammation of the skin around the edges of the nail and by other fungal infections of the nail. To correctly diagnose nail psoriasis, you should consult a doctor who will do a thorough medical assessment and perhaps a diagnostic test such as nail bed biopsy.