Nail psoriasis causes visible changes to the nails such as discoloration and separation. Doctors may use nail psoriasis scoring systems or severity indexes to assess symptoms.

Nail psoriasis causes various symptoms on the fingernails and toenails, such as nail separation, discoloration, or crumbling nails. It is a type of psoriasis, which is an immune-mediated condition that affects the skin.

Doctors may use a scoring system called the Nail Psoriasis Severity Index (NAPSI) to determine the severity of a person’s symptoms.

The results may help doctors recommend suitable treatments, including topical creams, corticosteroid injections, or oral medications.

This article looks at nail psoriasis in more detail, including the possible symptoms, the scoring systems that doctors may use to diagnose the condition, and the treatment options.

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Nail psoriasis is a condition that can affect people with psoriasis. Psoriasis is an immune-mediated condition in which the immune system attacks healthy tissue, resulting in inflammation and faster skin cell growth that can cause plaques and scales to form on the skin.

Psoriasis can affect different organs and tissues throughout the body, including the nails and the joints.

According to the National Psoriasis Foundation, about 50% of people with psoriasis have psoriasis on their nails, while close to 90% of people with psoriasis will have nail psoriasis at some point during their life.

Learn more about nail psoriasis.

The NAPSI is a scoring system that doctors can use to evaluate the extent of nail psoriasis.

NAPSI divides each nail into quadrants. A doctor will examine each quadrant and score it depending on which clinical signs or symptoms are present.

A 2019 study notes that these signs include:

  • pitting
  • white lines or dots
  • red spots on the lunula, which is the semicircle at the base of the nails
  • crumbling of the nail
  • area of discoloration on the nail, called an oil drop or salmon patch
  • onycholysis, which is the separation of the nail from the nail bed
  • hyperkeratosis, which is when a chalky substance builds up underneath the nail
  • small blood spots under the nail, which may resemble a splinter

The doctor will score the nail bed and the nail matrix, which is the area of specialized cells at the base of the nail that produces the nail plate. They assign each a score of 0–4, depending on the number of affected quadrants. This creates a total score of 0–8 for each nail.

A doctor will then add up the NAPSI scores for all the fingers, thumbs, and toenails they have examined, giving them a final total NAPSI score in the range of 0–160.

A score of zero means that no signs are present, and the numbers increase with the quantity or severity of symptoms present. The higher the NAPSI score, the more severe the nail psoriasis.

The Severity of Nail Psoriasis Score (SNAPS) is another scoring system that doctors may use to evaluate the severity of nail psoriasis. SNAPS looks for four signs of fingernail psoriasis:

  • pitting
  • separation of the nail from the nail bed
  • hyperkeratosis
  • severe deformity of the nail

Depending on the severity of these signs, a doctor will determine a SNAPS score in the range of 0–40.

Treatment for nail psoriasis may take time because the nails grow slowly. The American Academy of Dermatology Association (AAD) suggests that it may take 6 months or more to clear certain symptoms, such as a buildup of debris under the nail.

People may need to apply topical treatments one or two times a day for several months to treat nail psoriasis.

A doctor may sometimes create a treatment plan that includes a combination of treatment options. One type may be topical treatments, which are those that people apply directly to the nails. Examples include:

  • Corticosteroids: Strong corticosteroids can be effective for most symptoms of nail psoriasis. People may need to use corticosteroids one or two times a day for up to 9 months.
  • Calcipotriene: Calcipotriene (Dovonex) may be as effective as corticosteroids for treating buildup underneath the nail.
  • Tazarotene: Topical tazarotene (Tazorac) may be particularly effective for treating separation of the nail, pitting, and discoloration.

If topical treatments are not effective, people may require medical treatment at a doctor’s office. Medical treatment options may include:

  • Corticosteroid injections: A doctor will inject corticosteroids into or around the nail. Corticosteroid injections can help treat nail separation, ridges, buildup under the nail, and thickening. People may require repeat injections.
  • Lasers: Laser treatment targets the area of psoriasis with an intense beam of light.
  • Psoralen and UVA light (PUVA): PUVA is a treatment that may help treat nail discoloration and separation. People take a medication called psoralen orally or apply it topically to the nails and then expose the affected area to UVA rays.

For severe cases of nail psoriasis, people may need to take an oral medication that works throughout the body to treat psoriasis. These medications include:

  • methotrexate
  • retinoid
  • biologics
  • cyclosporine
  • apremilast

Learn more about oral medications for psoriasis.

People will need to contact a primary care physician or dermatologist if they notice any unusual changes to their fingernails or toenails.

The healthcare professional will be able to examine the nails and determine whether the symptoms are due to nail psoriasis or another condition, such as a fungal infection.

It is important to treat nail psoriasis to prevent the symptoms from worsening or becoming painful. Without treatment, the nails may deteriorate, and a person could find it difficult to use the hands or feet.

Changes to the nails may also be a sign of psoriatic arthritis, a type of arthritis that can affect some people with psoriasis. The early diagnosis and treatment of psoriatic arthritis are important to prevent the condition from worsening.

Learn about the differences between nail psoriasis and nail fungal infections.

The outlook for people with nail psoriasis may depend on the severity of the symptoms. Nail psoriasis symptoms may fluctuate over time, and although they will resolve by themselves in some cases, treatment will be necessary in others.

Relapses are common for people with nail psoriasis, so it can be beneficial to find ways to manage the symptoms in the long term.

A range of treatments can effectively treat the symptoms of nail psoriasis, but it may take several months of regular treatment to see results because nails grow slowly.

Nails psoriasis is a form of psoriasis that affects the nails, causing symptoms such as crumbling, pitting, discoloration, and separation of the nail from the nail bed. It can occur in the fingernails or toenails.

Doctors may use a scoring system, such as NAPSI or SNAPS, to determine the severity of the symptoms.

The treatment options for nail psoriasis include corticosteroids, topical ointments, and oral medications.

Anyone who notices any signs of nail psoriasis should contact a doctor or dermatologist. Treatment can help clear the symptoms and prevent the condition from worsening.