What Is Nail Psoriasis?

Overview

Psoriasis is a common disorder often associated with skin, but it can also affect other parts of the body, such as joints and nails. 

The nail, despite its small size, is made of different parts that can be broken down into different sections. The nail consists of 

• Nail plate- the hard plate that is what we think about when talking about the nail
• Nail folds- the skin that surrounds the edges of the nail plate
• Nail bed- the skin underneath the nail plate
• Nail matrix- this is part of the nail bed closest to the knuckle and is where new cells thatmake the nail plate are formed
• Eponychium- the cuticle
• Lunula- this is the white half-moon on the nail plate and is what the nail matrix looks like through the nail plate¹

Psoriasis is a chronic inflammatory disorder and can involve the nail matrix or nail bed, leading to changes in the nail, known as nail psoriasis.² 

Causes of nail psoriasis

Nail psoriasis is an autoimmune condition, meaning that it is caused by your immune system not functioning properly. Its exact cause is unknown, however, it is theorised that this dysregulation of the immune system causes skin cells to form more quickly. Normally, new skin cells grow every month, however, in people with psoriasis, this process happens more frequently, with new skin cells forming every three or four days, and often do not reach full maturity.³ Genetics are expected to play a strong role in developing nail psoriasis, as it is common for people within the same family to develop psoriasis. 

Signs and symptoms of nail psoriasis

Nail psoriasis can affect any nail , signs to look out for include 

• Nail pitting- the formation of dents or pits on your nail
• Leukonychia- a complete or partially white nail
• Nail ridges- these can either be going across your nail (Beau lines) or down the nail
• (Onychorrhexis). These ridges can develop into larger splits or fissures
• Nail crumbling
• Onycholysis- lifting of the nail plate away from the nail bed
• Nail discolouration- the nail bed may change colour to salmon-pink patches, that can also be yellow or brown
• Subungual hyperkeratosis- excessive production of skin cells that accumulate under the nail bed. This leads to the thickening and lifting of the nail, causing it to become yellow-white
• Splinter haemorrhages- these are tiny splinter shapes dark spots on the nail that are caused by the small blood vessels underneath the nail plate rupturing. They are usually found towards the end of the nail 

Due to these nail changes, people with nail psoriasis may also experience symptoms such as 

• Tenderness
• Pain 
• Changes in sensation to fine touch 
• Difficulty picking up or using objects

Nail psoriasis is nowhere near a life-threatening condition, however, it can affect your ability to work, your social life, and your mental health. In severe cases where the nail plate becomes damaged, the nail can become infected with a fungus, in a condition known as onychomycosis.^3,4

Additionally, symptoms of psoriatic arthritis may be present, such as pain, swelling, and stiffness in any joint of the body, but most typically in the knees, ankles, hands, and feet. Symptoms of nail psoriasis and psoriatic arthritis do not have to be present at the same time, as the severity of the condition can improve over time (remission) and also get worse (relapse).⁵

Management and treatment for nail psoriasis

To reduce the risk of damaging your nails further, it is recommended to keep nails affected by psoriasis short and to cut off any hangnails. Washing your hands and nails regularly can help prevent infection. Wearing gloves during activities that can irritate the skin, such as washing up dishes, can help reduce further irritation to the skin.³

Medical treatment involves either applying the medication directly to the affected nail (topical) or taking tablets (systemic treatment). Both have their advantages and disadvantages, and factors such as the severity of the disease, the age of the patient, and the presence of other conditions may affect the decision on what treatment would be best suited. 

For mild nail psoriasis, when only one or two nails are affected and there are no other significant symptoms, topical treatment is the best course of action.  

Topical treatment: 

• Steroids- anti-inflammatory medication that can be applied as nail polish or cream. Topically, steroids cause few side effects, however, if applied for too long, they can lead to a variety of skin conditions, such as stretch marks, and easy bruising
• Vitamin D analogues- (Calcipotriol) work by reducing the overproduction of skin cells and helping them reach full development
• Calcineurin inhibitors- Tacrolimus reduces the activity of the immune system and is used if steroids are not working. They may cause itching or burning when first used, however, this tends to subside after the first week

Taking medication is the best course of action for patients who did not respond to topical treatment, or in cases of severe nail psoriasis involving multiple nails . 

Systemic treatment: 

• Methotrexate- is a powerful anti-inflammatory drug that  can also be used to treat cancer. It is effective at treating skin disorders, and can results can be seen in several weeks. However, it has many side effects, is not recommended for pregnant women, and is best avoided in patients with liver and kidney disease
• Retinoids- (Acitretin) are used in severe cases of psoriasis and slow  down the production of skin cells. Side effects include dry lips and eyes, skin peeling, and increased susceptibility to sunburn
• Biological agents for psoriasis- (infliximab) are drugs made from living material, such as from humans, plants, or animals. These are also called targeted therapy, as unlike the other drugs mentioned here, they interfere with a specific part of the immune system, not just all of it. Targeted therapy is the most effective method of treating psoriasis with fewer side effects, however, they are expensive, and not readily available to everyone

Besides medication, other therapies are available

• Phototherapy- ultraviolet light is used to slow down the production of skin cells. Each session takes only a few minutes but will be needed two or three times a week for several weeks. Another topical called Dithranol may be used together with phototherapy
• Lasers- pulsed dye lasers used are used to target the small blood vessels beneath the nail bed, using heat to kill diseased cells
• Photodynamic therapy- natural light is used alongside a solution that  increases light sensitivity^2,4,6

It is also important to note, that due to the slow growth of the nail plate, it can take months before any changes can be seen from treatment. 

FAQs

How is nail psoriasis diagnosed

Since the nail changes in nail psoriasis are so characteristic, the diagnosis of nail psoriasis is based on these findings. Additionally, your healthcare provider may ask you if anyone in your family suffers from psoriasis.  

To help grade your nail psoriasis, a scoring system called the nail psoriasis severity index (NAPSI) is used to help establish the severity of the condition. The nail is divided into four equal quadrants and each quadrant is assessed for the presence of any nail changes due to psoriasis. If signs of psoriasis are present, the quadrant will square 1 point. Overall, your nail will receive a score from 0-4, with a higher number indicating more severe psoriasis. 

To rule out a fungal infection, samples of your nail may need to be taken. Nail clippings can be examined under the microscope or further testing if your healthcare provider is uncertain of the cause of your nail changes.^2,3

How can I prevent nail psoriasis

Since there is no direct trigger cause of psoriasis, there is no way to prevent it. Treatment and looking after your nails can help manage symptoms, and they may come and go throughout your lifetime. 

Is nail psoriasis contagious

Since nail psoriasis is not an infectious disease, it is not contagious. You cannot contract nail psoriasis through contact with a person with nail psoriasis.³

Who are at risk  of nail psoriasis

Nail psoriasis can affect anyone of any age, sex, or ethnicity, and has not been reported to be higher in a specific group. It is very common in people with other forms of psoriasis, such as chronic plaque psoriasis, with over 90% likely to develop nail psoriasis at some point in their lifetime.⁴

How common is nail psoriasis

Nail psoriasis is more common if you already have other forms of psoriasis, and be seen in up to 80% of patients with psoriatic arthritis. It is much rarer to have nail psoriasis on its own, and only makes up about 5-10% of cases.⁷

When should I see a doctor

If you have noticed any change in your nails or are worried you may have an infection, seek advice from your healthcare provider. Additionally, if you are receiving treatment for nail psoriasis and you are concerned that it is not helping, get in touch with your doctor to consider changing your treatment. 

Summary

Nail psoriasis is a chronic disorder of the nail and surrounding skin that is more common for individuals with other forms of psoriasis. There is no direct cause or any way to prevent this condition. Symptoms of nail psoriasis may wax and wane throughout your lifetime, and looking after your nails and seeking medical treatment when flare-ups occur can help manage it.