Psoriasis is a disease that affects the skin causing redness and raised patches, but it can also affect one’s finger or toenails. Here in the U.S., about 7 million people have skin psoriasis and 10-55% of them develop nail psoriasis. It is less common for a person to have nail psoriasis alone (only 5%) without also having skin involvement. In addition, 53-86% of those with psoriatic arthritis also have nail psoriasis. (webmd)
How psoriasis affects the nails:
Psoriasis can affect the growth of the nail minimally or more severely. The exact mechanism is not known, but the nail matrix is the part of the nail that becomes deformed causing malformations of the nail plate (the actual large area we think of as our nails) as it grows. Depending on the areas of inflammation, the nail will show different changes as indicated below. (emedicine.medscape)
Symptoms of nail psoriasis:
• Pitting: one of the more common problems and occurs from loss of cells on the nail surface.
• Oil drop appearance: often called a salmon patch as it appears reddish/yellow and usually is an indicator of nail psoriasis.
• Discoloration: whitish nail plate due to defects in keratin or reaction of the nail cells to the psoriasis
• Thickening underneath the nail leading to lifting (onycholysis) or loosening caused by excess production of keratin.
• Beaus lines: horizontal lines that occur from disruptions in the nail keratin and inflammation.
• Crumbling: due to weakening of the nail bed or matrix
• Splinter hemorrhages: thin black lines due to small bleeds from the capillaries between the nail and the bed underneath.
• Arthritis in the fingers: occurs in 53 to 86% of people with nail psoriasis.
A doctor must evaluate your nails to determine if the problem is solely related to psoriasis or whether another infection has affected the nail. If there is also fungus growing in the nail, then it must also be treated.
Creams may be prescribed that may include steroids or other vitamins to moisturize the nail bed and reduce inflammation, or topical 5-fu cream may be used.