Nail psoriasis refers to changes that occur in the fingernails and toenails when a person has psoriasis. These changes range from discoloration to alterations in the nail bed.

Nail psoriasis can have a physical and emotional impact on a person's life. It affects up to 50 percent of people who have psoriasis and as many as 80 percent of those with psoriatic arthritis. It may also occur in a person with no history of psoriasis.

What is nail psoriasis?

Psoriasis is a chronic disease of the immune system that varies from mild to severe.

The condition starts beneath the skin, although it tends to be seen as a skin condition.

Normal functioning skin cells reproduce every 28 to 30 days. In a person who has plaque psoriasis, an overactive immune system causes the skin cells to reproduce every 3 to 4 days. As a result, the visible skin appears thick and red, and it feels itchy.

Nail psoriasis often occurs with psoriasis because nails are part of the skin. They grow from the nail root, which is under the cuticle. The psoriasis forms in the nail root.

Signs of psoriatic nails include pitting. Up to a dozen shallow or deep pits may appear on the surface of the nails. The nails may also split, thicken, crumble, or pull away from the finger.

This can make it difficult to carry out tasks, such as sewing.

Other changes that may occur include:

Onycholysis: If the nail becomes detached from the nail bed and leaves a gap, an infection can develop in the nail and the skin. The nail tip may develop a yellowish patch that extends to the cuticle.

Subungual hyperkeratosis: A chalky substance may develop under the nail, causing a gap. The nail might feel uncomfortable and painful when pressure is applied to it. The toenails may hurt when wearing shoes.

Discoloration: Nails become discolored, often showing a yellow-brown color.

Deformation: Nails can alter in shape and size without any other cause.

Onychomycosis is a simple fungal infection that can cause the nail to thicken. It is often diagnosed separately from psoriasis. Treatment normally involves antifungal medications that target the whole body. For a person with psoriasis, this will be taken into account when choosing a treatment.

Treatments for nail psoriasis

Nail psoriasis does not always cause physical pain, but it is often unsightly, and it can cause embarrassment. Appropriate treatment can prevent the condition from worsening.

Prescription treatments

A doctor can diagnose nail infections and nail psoriasis. Around one third of people with nail psoriasis will also have a fungal infection. A doctor can prescribe medication to treat both at the same time.

Doctors commonly prescribe terbinafine (Lamisil) and itraconazole (Sporanox) for nail psoriasis, but these drugs can produce adverse effects. These side effects range from skin rash to liver damage.

Unlike fungal infections, nail psoriasis happens when the nail is forming. Topical medications may never reach the problem area, so doctors usually prescribe oral medications.

Some people who have nail psoriasis have been given corticosteroid injections into the nail bed. This has produced positive results, especially when it was used alongside topical treatments. To minimize the pain of the injection, a numbing agent may be used as a local anesthetic.

Some people have their nails repaired cosmetically, which includes nail scraping and filing. The nail can be removed through surgery, X-ray therapy, or by applying a high concentration of urea. However, it may still have an abnormal appearance when it grows back.

If the infected nails are painful, a doctor may prescribe painkillers. If the nail psoriasis is causing severe disabilities, such as not being able to walk, then a doctor might prescribe systemic medications. These drugs affect a person's whole body, not just the problem areas.

Examples of systemic medications include methotrexate, cyclosporine, or biologics. However, it can take a long time for the nail to improve, because the nail that is visible is not the one that is forming.

Cosmetic treatments

Nail psoriasis can be unsightly and cause embarrassment.

Manicures, pedicures, and nail painting can "hide" the appearance of discolored nails. Filing and shaping nails can make misshapen nails look much better. Some people attach artificial nails to improve the appearance of their nails, but the chemicals in the glue can damage and irritate the nail bed further.