Psoriasis is a common autoimmune condition that causes dry, scaly skin.

With psoriasis, skin cells are produced faster than your body needs them. The layers build up on each other and become irritated. Psoriasis scales will appear most often on the knees and elbows but also sometimes on the hands, feet, scalp, or face.

Up to 55% of people with psoriasis may have nail psoriasis. This is when psoriasis spreads to the fingernail beds and the nail matrix. When psoriasis spreads to the nails, it can make them discolored, pitted, or brittle. Sometimes, red or white spots will appear or the nails can even separate from the nail bed.

Doctors have developed a way to measure the effects of nail psoriasis, called the nail psoriasis severity index (NAPSI). It’s a standardized and objective way of tracking the progression of nail psoriasis.

Healthcare professionals can perform the NAPSI test quickly, and it delivers consistent results, according to research from 2003.

Read further to learn more about NAPSI and what to do if you think you might have nail psoriasis.

Usually, you will see a dermatologist or rheumatologist to have the test done. The test to score your NAPSI is entirely noninvasive and painless. In fact, all a doctor needs is a pencil and a notepad.

Here’s how it works:

  1. First, the healthcare professional will divide the nail bed and nail matrix of each finger or toe into four imaginary sections. The nail bed is the firm, fleshy part of your fingers and toes that lies underneath your nails. It’s the part that’s exposed if you lose a nail. The nail matrix is the area at the base of the bed that produces the skin cells that grow to become your fingernails and toenails.
  2. After making the imaginary lines on each bed and matrix, the doctor will then check each quadrant to see how many of the eight common signs of nail psoriasis are in each one.
  3. Each section with at least one symptom is given one point, and all the points are added up. If you have all your fingernails and toenails, your maximum score for the NAPSI would be 80 for just hands or feet, and 160 for both.
  4. If doctors want a more detailed measurement, they can score each quadrant for each possible symptom, meaning a total of 32 possible points for each finger or toe. This is rarely done since the basic test usually provides doctors with enough information.

NAPSI is very simple to understand: the higher the score, the more severe your nail psoriasis is. A score of 0 means you have no signs of the condition, while higher scores indicate more significant symptoms.

The index is helpful for people receiving psoriasis treatment, as well as people in clinical trials.

Doctors will use your NAPSI score to help them track the progress of your psoriasis as it develops and the effectiveness of any treatment as it gets better. The index is especially useful in trials because it gives doctors a reliable way to take accurate measurements of the progress of a large number of people.

One big advantage that the test provides is its consistency. According to a study from 2012, people with nail psoriasis will receive around the same NAPSI score when given the test by different healthcare professionals.

Many treatments exist for nail psoriasis, though it’ll take time before you’ll see results. This is because new cells are created at the base of the nail and can take a long time to grow in. Topical medications like corticosteroids, calcipotriol, or tazarotene can help, but you need to apply them at least once daily for months to be effective.

Cyclosporin A and vitamin D3 analogues have also proven helpful in treating nail psoriasis and are sometimes given along with other medicines, according to 2016 research.

For slightly more stubborn nail psoriasis, a healthcare professional might inject corticosteroids or use more advanced and less painful treatments that combine ultraviolet light with a specific medication or lasers.

In extreme cases of nail psoriasis, oral medications may help. These include:

  • methotrexate
  • cyclosporine
  • apremilast

Certain retinoids or biologics may also help.

If you notice a sudden difference in the appearance of your nails, such as a change in color or red or white spots, you should reach out to a doctor. You’ll want to do the same if your nails become brittle or crumble, or if they start to separate from the nail bed.

If nail psoriasis has progressed so far that you are having trouble with everyday tasks like walking, tying your shoes, or buttoning your shirt, you should also see a doctor.

If you ignore nail psoriasis long enough, it can eventually make it hard to walk without pain or do everyday tasks. A doctor will probably first check to see that your symptoms aren’t caused by nail fungus, which is also very common.

Nail psoriasis affects more than 7 million people each year in the United States alone and can be very uncomfortable.

NAPSI is an accurate way to measure the progress of nail psoriasis. This can help your doctor advise you on the many safe and effective methods to treat it.