Overview of Nail Psoriasis

Nail psoriasis causes damaged, split, or lifted nails. Psoriasis on the nails typically occurs with other symptoms of psoriasis, including itching, redness, scaling, and the formation of thickened patches called plaques. If nail psoriasis occurs on its own, it can be hard to diagnose and is easily confused with other conditions.

You may feel self-conscious about how your fingernails or toenails look or have pain that makes it hard to walk, jog, or do manual labor. Psoriatic nail disease can also lead to progressive damage to the nails.

This article reviews the causes, symptoms, and treatment of nail psoriasis. It also shows photos of nail psoriasis so you can see what it looks like.

What Causes Nail Psoriasis?

Nail psoriasis is an autoimmune disease like skin psoriasis. Autoimmune means that the body's immune system sees normal tissues as harmful and attacks them.

Although the skin is the main target of psoriasis, other tissues are affected, too. The inflammation that is caused by the attack triggers more cells (keratinocytes) to be made in the skin, nails, and other tissues.

When it happens in the skin, psoriasis plaques develop. When it happens in the fingernails and toenails, the production of too many keratinocytes can cause thickening, malformation, and discoloration because the cells are being made faster than they can be shed.

Nail psoriasis cannot be spread to another person since it’s an autoimmune disease, not an infection. 

What Nail Psoriasis Looks Like

The symptoms of nail psoriasis vary from one person to the next and can change over time. In general, there are some key signs of nail psoriasis that affect how the nail looks.

Some of the telltale signs of nail psoriasis are:

• Changes in how the nails look. Psoriasis can cause tiny dents or dots in the nail (pitting). It may lead to some grooves or lines running from side to side on the nail (Beau's lines). You may notice small black lines running from the tip of the nail to the cuticle that are caused by burst blood vessels (splinter hemorrhages).
• Changes in the nail texture. Nails affected by psoriasis can get thick (subungual hyperkeratosis) or may get too thin and start to lift up from the nail bed (onycholysis). Overall, your nails can become brittle and dry and may crumble.
• Variations in nail color. You may notice yellowish-red dots under the nail (oil drops or salmon patches), white patches (leukonychia), and/or redness in the white arch at the base of the nail (spotted lunula).
• Pain and other symptoms. Some people with nail psoriasis also have arthritis in the finger or toe that has damage (psoriatic arthritis).

Nail psoriasis symptoms can show up on both the nails of the toes and fingers, but it’s more common to see them on the fingernails. The condition usually affects a few digits, rather than just one.

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How Is Nail Psoriasis Diagnosed?

There are no blood tests or imaging studies to diagnose psoriasis. Like psoriasis of the skin, psoriatic nail disease is diagnosed by having your provider do a physical examination and talk to you about your medical history (including your family's history of skin disorders).

Your provider may want to take nail clippings or a tissue sample from your nail bed so they can look at them with a microscope.

Under a microscope, psoriatic tissues will typically have cells that are dense and tightly compacted (acanthotic).

If the nails are affected by psoriasis but not the skin, your provider will want to rule out other possible causes before diagnosing you with psoriasis. 

This process is called a differential diagnosis. As they investigate, your provider might use tissue biopsies, lab cultures, and other tests to see if another condition is causing your symptoms. The differential diagnosis for psoriasis includes:

• Alopecia areata (an autoimmune disease characterized by hair loss and nail damage)
• Lichen planus (an inflammatory condition affecting the skin, nails, and hair)
• Onychomycosis (a common fungal infection of the nail)
• Pityriasis rubra pilaris (a rare disorder that causes skin inflammation, the thickening of nails, and hair loss)

Nail Psoriasis Treatment

Treating nail psoriasis can be slow and frustrating, partly because of the nail growth cycle. It takes about three months to regrow a fingernail and six months to regrow a toenail. You’ll usually need to stick with your treatment for at least that long before your nails will start to look normal again.

Treatments for nail psoriasis can be topical, oral, or injected. Your provider might want you to use more than one treatment. 

Topical Steroids

Topical steroids are sometimes used to reduce localized inflammation. While helpful in treating skin psoriasis, they can be hard to apply to the nails.

Liquid steroid drops are usually put on the underside of the nail tip and other areas where the skin and nail meet.

Overusing topical steroids can lead to permanent skin thinning (atrophy) in the treated area.

Calcipotriol

Calcipotriol comes from vitamin D. It is applied topically twice daily to the affected nail. It is available in a 50-micrograms-per-gram (mcg/g) formulation.

A 2014 review of studies reported that when used for three to six months, calcipotriol creams were just as effective as topical steroids in improving nail psoriasis symptoms.

Tazarotene

Tazarotene is a topical retinoid product used to treat acne and plaque psoriasis. Several studies have shown it to be safe and effective at treating nail psoriasis as well.

Steroid Injections

Steroid injections are given in small doses directly into or near the structure of the nail to treat nail psoriasis.

Triamcinolone acetonide is the most commonly used steroid that is put directly into the affected area (intralesional). It’s usually prescribed in a single 0.1-milliliter (mL) injection given in four places around the nail. Pain is the most common side effect of the treatment.

Systemic Therapies

Severe nail psoriasis may need treatment that targets the whole body, not just the nails. Systemic therapies to treat nail psoriasis use medications that quiet the immune response that triggers nail changes.

These therapies include older disease-modifying anti-rheumatic drugs (DMARDs) like methotrexate and Sandimmune (cyclosporine), as well as newer biologic drugs like Otezla (apremilast), Humira (adalimumab), and Cosentyx (secukinumab).

Other Treatments

There are other treatments used for nail psoriasis, but some are more effective than others. 

One example is phototherapy using ultraviolet (UV) lamps. This treatment has proven beneficial in treating plaque psoriasis, but it only appears effective in treating oil spots in nails.

While oral retinoids like acitretin can treat nail psoriasis, their benefits depend on the dose.

If more than the smallest dose necessary is used, oral retinoids can make symptoms like nail crumbling worse and may lead to an infection of the skin folds around the nails (paronychia).

Summary

Nail psoriasis is caused by the same immune system response as skin psoriasis. Your provider can look at your nail changes and see if they are typical of psoriasis or are more likely being caused by another condition.

Many treatments, like prescription medications, are used to treat nail psoriasis. Other options like phototherapy might help, but they are not always as effective for nail psoriasis.