Nail psoriasis is a special form of psoriasis in which the nails on the hands and / or feet are affected. Doctors call this type of disease psoriatic onychodystrophy (from the Greek.onychosi- nail,dis- infringement,trophe- food).
From this article you will learn about the causes of the development of nail psoriasis, its symptoms, which do not always unequivocally indicate an accurate diagnosis, as well as dangerous misconceptions about this form of the disease.
Note.There are many photos in the article that can scare the unprepared reader.
Where do nails grow from?
To understand the problem of nail psoriasis, it is important to understand how the so-called nail apparatus works.
The nail has two functions: working and aesthetic. First, the nail protects the fingertips from damage, increases precision and sensitivity when working with small objects, can be a weapon for attack or defense, and finally, with the help of itchy nails. Secondly, the aesthetic or cosmetic function of the nail is also important, especially for women.
Nails are formed from the outer layer of the skin - the epidermis. The nail device includes:
- nail plate - the nail itself,
- matrix - produces nail plate,
- the nail hole, or lunula, is the only visible part of the matrix, this is a white moon-shaped area at the bottom of the nail plate,
- eponychium - a nail roller that protects the matrix from above from damage,
- nail - is located under the nail plate and is responsible for its attachment to the phalanx of the fingernail,
- hyponychium - the transition zone between the nail bed and the skin of the fingertip.
Causes and mechanism of nail psoriasis development
In its course - with periodic exacerbations and remissions - psoriasis on the nails resembles a vulgar form of the disease.
It is believed that psoriasis on the nails develops for the same reasons and in the same pattern as typical psoriatic eruptions. Among these reasons, external and internal factors are distinguished.
The main essential factor is genetic predisposition. External causes are numerous and include, for example, injuries, poor diet, narcotics (alcohol and tobacco), infections, and certain medications.
The standard mechanism of development of nail psoriasis under the influence of these reasons can be briefly described as follows:
- Provoking factors, such as trauma, activate immune cells.
- Activated immune cells migrate to the area of the nail matrix or nail bed.
- Immune inflammation develops in these areas.
- The division of skin cells is rapidly accelerated, and their maturation is disturbed.
- There are characteristic symptoms of psoriasis on the nails.
Also, the cause of nail psoriasis can be considered the result of the inability of the organism to adapt to unfavorable environmental conditions. According to this view, the main cause of psoriasis is an evolutionarily foreign habitat.
As a consequence, this evolutionary approach to unhealthy diet, lack of sun and clean water, excess toxins, lack of normal physical activity, sleep disorders and chronic stress is considered a direct cause of the disease.
Nail psoriasis and psoriatic arthritis are related
The connection between nail damage and psoriatic arthritis has been known for a long time.
Based on the observations, the scientists found that psoriatic arthritis accompanies nail damage in nine out of ten cases.
But the mechanism of this connection has not been fully studied. However, the authors of several studies, for example, from the Institute of Molecular Medicine in Leeds (UK), have tried to explain this connection outside the concept of immune inflammation.
In their opinion, the fact is that the finger joint is located next to the nail and is anatomically connected to it.
Therefore, microtrauma and the Kebner phenomenon that cause primary inflammation of the joints - psoriatic arthritis - also cause secondary pathological changes on the nearest nail.
This is why psoriatic arthritis is so often associated with nail damage.
%20of%20the%20toes.jpg)
Thus, the symptoms of nail psoriasis often indicate psoriatic arthritis.
Let us now look at the main myths that accompany this disease and how dangerous they are.
Myth 1: Psoriasis on the nails is rare.
Not really. Nails often seem to suffer from psoriasis.
According to various sources, psoriasis on the nails occurs in the range of 6% to 82% of cases of psoriasis vulgaris. Such a wide distribution in the assessment of the prevalence of this pathology is explained by the problems in its accounting. Medical statistics record doctor's visits primarily to patients with a vulgar shape, and elsewhere attention is paid to nails. In scientific research, cases of nail psoriasis are also usually studied only in addition to the main subject of interest - psoriasis with skin lesions.
However, numerous publications say so
up to 80-90% of patients with psoriasis vulgaris reported recurrent nail damage.
And that nail psoriasis occurs in 90% of patients with psoriatic arthritis and scalp psoriasis.
It should be borne in mind that adults usually suffer from this form of the disease.
According to various sources, in children, nails are affected in about 7-37% of cases of psoriasis. Unfortunately, often the manifestations of psoriasis on a child's nails are not given due importance. Parents or doctors believe that this is a variant of the norm or a consequence of trauma or simply do not notice it due to the mild severity of the symptoms.
Myth 2: It is easy to recognize nail psoriasis by its symptoms
In fact, not always. The fact is
The nail is able to respond to various diseases with only a limited number of symptoms. Therefore, the manifestations of different nail diseases can look the same.
Of course, nail psoriasis can be suspected if the patient has severe symptoms of vulgar psoriasis. However, nail lesions can be smaller than skin lesions and can be easily ignored by a doctor.
Usually, the more active the psoriasis on the skin, the more severe the nail damage.
First of all, the nails are affected.
It is also important to know that in 5% of cases, nails may be the only initial manifestation of psoriasis. That is, the classic manifestations of psoriasis on the skin can be completely absent.
What nail psoriasis looks like depends on where the pathological changes come from - in the matrix or layer of the nail.
The source of the symptoms - the matrix or the bed - is important to consider when choosing a treatment. Therefore, it needs to be properly defined.
Symptoms originating from the nail matrix are:
- thimble symptom,
- white spots and spots (leukonychia),
- red dots on the hole,
- crumbling nails.
Although the cause of these symptoms is at the level of the matrix, as the nail grows, pathological changes appear on the nail plate.
The symptoms, the cause of which is in the nail bed, are:
- nail separation (onycholysis),
- longitudinal bleeding,
- subungual hyperkeratosis,
- oil stain symptom.
We will continue to dwell on each symptom separately. And let's start with the manifestations that come from the matrix.
Thimble symptom
The thimble symptom appears on the surface of the nail plate with holes or dimples that look like indentations on the thimble.
Such defects occur mainly on the toenails, but rarely occur on the feet. As the nail grows, the pits move from the crease of the nail to the edge of the nail plate.
The pits in nail psoriasis are usually deep, large and chaotic. They are caused by the extraction of loose clusters of cells from the surface of the nail, with damaged division and keratinization.
The more severe the psoriasis, the more often the thimble symptom occurs.
However, it should be borne in mind that, in addition to psoriasis, pits on the nails are also characteristic of alopecia areata (alopecia), eczema, dermatitis, and can also occur, for example, in fungal infections.
Counting the total number of pits on all nails will help in making a correct diagnosis.
- Less than 20 - not typical for psoriasis,
- from 20 to 60 - psoriasis may be suspected,
- more than 60 - confirm the diagnosis of psoriasis.
White spots (leukonychia)
Leukonychia is a symptom that manifests as white spots or spots on the nails.
S leukonychia (from grc.leukós- white andonychosi- nail), in contrast to the superficial pits in the thimble symptom, cells with impaired division and keratinization are located in the thickness of the nail plate. At the same time, the nail surface remains smooth. And the white color of the spots is created by the reflection of light from clusters of loosely placed cells.
However, some research suggests that leukonychia is so common in healthy people that it is not the main symptom of psoriasis. For example, a manicure injury can cause leukonia.
Broken nails
When superficial pits (a symptom of a thimble) and deep zones of leukonychia (white spots) merge, the nails begin to crumble.
Nail crumbs usually occur with long-term nail psoriasis.
And the more intense the inflammation of the nail matrix, the more the nail plate is destroyed. In severe cases, the nail may completely collapse and fall out.
Red dots on nail bushes
Apparently red spots in the area of the hole and its general redness occur due to increased blood flow in the vessels under the nail.
Also, red dots on the hole occur due to a violation of the structure of the nail plate itself: it becomes more transparent and thinner. And because of that, firstly, the vessels become better visible, and secondly, the thin plate of the nail puts less pressure on the vessels below it and they are more filled with blood.
Thinning of the nail plate can also cause redness of the entire nail layer.
Nail separation (onycholysis)
Now let's look at the symptoms whose source is the nail bed.
Onycholysis is the separation of the nail plate from the layer due to the accumulation of cells under the nail with impaired division and keratinization.
Onycholysis itself (from the Greek.onychosi- nail andλύσις- separation) is not necessarily a sign of psoriasis and can develop, for example, as a result of a nail injury.
Initially, the loss of contact between the nail and the bed occurs in the zone of hyponychia - along the outer edge of the nail plate. Then the onycholysis spreads towards the crease of the nail in the form of a semicircular line. The peeling area becomes white due to the accumulation of air under the nail.
A reddish border (scientifically erythema) along the edge of onycholysis, which is usually visible on the fingers, is characteristic of psoriasis and helps in making a correct diagnosis.
With prolonged onycholysis, the nail bed loses its properties and the growing new nail will most likely not be able to attach to it normally. Therefore, even with complete restoration of the nail plate, onycholysis often lasts.
Due to the fact that onycholysis facilitates the penetration of bacteria and fungi, infection can join. This sometimes leads to a change in nail color. For example, a greenish color may appear when bacteria attachPseudomonas aeruginosa(Pseudomonas aeruginosa) and others.
Longitudinal subungual bleeding
Longitudinal subungual hemorrhages occur in the nail bed and look like dark red lines 1-3 mm long.
Increased blood flow and edema in the area of nail bed inflammation lead to capillary rupture, which manifests itself in the form of such bleeding.
Due to the peculiarities of the blood supply, most bleeding occurs closer to the free edge of the nail - in the zone of hyponychia.
Subungual hyperkeratosis
Subungual hyperkeratosis is an accumulation of dead cells under the outer part of the nail plate.
With psoriasis, subungual hyperkeratosis (from the Greek.hyper- excessive andkeras- horn) is usually silvery white, but can also be yellow. And when the infection joins, it can become, for example, greenish or brown.
The higher the nail rises above the nail layer, the greater the activity of the pathological process.
On the fingers, subungual hyperkeratosis is usually manifested by loose layers under the nail plate. On the feet, these masses are firmly soldered with a thickened nail.
Also, psoriasis with nail lesions on the feet is characterized by a combination of subungual hyperkeratosis and onycholysis (separation of the nail).
Symptom of oil stain
The symptom of an oil stain appears under the nail plate in spots of yellow-red (salmon) color.
They form on the nail bed closer to the crease of the nail and move towards the edge of the nail as it grows.
The cause of this symptom is inflammation of the nail bed with dilation of capillaries and accumulation of cells involved in inflammation, as well as cells of damaged division and keratinization.
Oil stains come in a variety of shapes and sizes. They can be found both in the center of the nail and on the edge, next to the onycholysis zone.
Myth 3: Nail psoriasis is just a cosmetic problem.
In fact, that is not true. Although over 90% of patients report tasteless nail psoriasis, this is not just a cosmetic issue.
According to various studies, nail psoriasis significantly reduces the quality of life of patients:
- 52% of patients also complain of pain,
- 59% - due to problems in daily activities,
- 56% - due to difficulties at home and
- 48% - due to difficulties at work.
Therefore, it is very important to correctly diagnose and start treatment as early as possible, because improving the condition of the nails significantly improves the quality of life of patients with psoriasis.
Myth 4: Nail psoriasis is not dangerous
In reality, this is not the case. Speaking above about the causes of this form of the disease, we have already written about it
nail psoriasis is an important symptom of psoriatic arthritis.
It is important to keep in mind that external manifestations of arthritis may be completely absent. In this case, we can talk not only about the affected joints of the toes and feet, but also the joints of the spine and pelvic bones.
You can check your joints for arthritis with ultrasound (ultrasound) or magnetic resonance imaging (MRI).
Even if there are no obvious symptoms of arthritis, but there are manifestations of nail psoriasis, it is very important to ensure that all joints are in order.
And then regularly monitor the condition of the joints. Otherwise, psoriatic arthritis can be easily missed! Late diagnosis will lead to late treatment and, as a result, to irreversible joint damage and disability.
Therefore, if the doctor did not order an insurance examination, stating the absence of visible signs of arthritis, you must go to the clinic yourself and pay for an ultrasound examination, for example.
How to diagnose nail psoriasis
It is important to know how to recognize the numerous symptoms of nail psoriasis, which we described above, because they help to establish an accurate diagnosis. But since nail changes characteristic of psoriasis can also occur in other diseases, it can be difficult to make a correct diagnosis right away.
In this case, the presence of several symptoms on different nails at the same time can help in the diagnosis.
Important signs of psoriasis on the nails are:
- thimble symptom: more than 20 pits on all fingernails indicate the possibility of psoriasis, and more than 60 pits confirm the diagnosis of psoriasis,
- nail separation (onycholysis) with a reddish border around the edge,
- oil (salmon) stains on the nail.
Difficulty in diagnosing nail psoriasis by one symptom
It is especially difficult to diagnose nail psoriasis if it occurs with only one symptom.
For example, if it is manifested only by onycholysis on the hands or only by subungual hyperkeratosis on the arms and / or legs.
The only method for making a reliable diagnosis in isolated onycholysis (nail separation) is probably the study of hyponychia using a special microscope - a dermatoscope.
A high-magnification video dermatoscope is used for this. Note that a hand-held dermatoscope does not provide the required magnification. A video dermatoscope with a magnification of at least 40 times is required. Then the enlarged capillary loops characteristic of psoriasis become visible.
In isolated subungual hyperkeratosis, the probability of psoriasis is high if the accumulation of scales under the nail is whitish-silver, as well as if all the nails on the hands or feet are affected.
Psoriasis or nail fungus?
Approximately 30% of patients with nail psoriasis also have a fungal infection - scientifically onychomycosis.
Externally, hyperkeratosis and onycholysis (nail separation) in psoriasis may resemble the manifestations of a fungal infection. Therefore, it can be difficult to perform a differential diagnosis, ie to determine the true cause of changes in the nail plate.
Moreover, both psoriasis and fungus can affect the same nails at the same time. It most often occurs on the fingers and is primarily characteristic of elderly patients.
Also, with a fungal infection, one or both nails on the big toes are often affected. In psoriasis, several nails are usually affected at once.
The following symptoms speak in favor of psoriasis:
- oil stains and / or fingernail symptom on the nails,
- signs of psoriasis on the scalp and / or large wrinkles of the skin,
- periodic remission and worsening of nail damage.
In favor of onychomycosis they say:
- longitudinal stripes on the affected nail,
- detection of fungi during examination under a microscope of scraping treated with potassium hydroxide from the affected nail (KOH test),
- positive culture on fungi.
In general, only on the basis of external manifestations, it is impossible to completely exclude fungal nail infection in patients with psoriasis.
It should also be borne in mind that a fungal infection can cause the Kebner phenomenon on the nail and the surrounding skin, resulting in psoriasis symptoms. In any case
it is useful to go to a mycologist and get tested for fungus and, if found, start antifungal therapy.
Important findings and what to do
Let's summarize important information about nail psoriasis and its symptoms.
Diagnostic features:
- Nail psoriasis is very common but often misses.
- Manifestations of psoriasis on the nails can be smaller, and even experts often do not pay attention to it.
- In 5% of cases, nail damage may be the only symptom of initial psoriasis.
- Manifestations of different nail diseases can look the same, which further complicates the diagnosis.
The main manifestations of nail psoriasis:
- thimble symptom - dimples on the nail,
- white dots,
- crumbling nails
- red dots in the area of the hole,
- nail separation,
- longitudinal subungual bleeding,
- subungual hyperkeratosis - loose clumps under the nail,
- oil stain symptom.
Psoriasis and fungi:
- Nail psoriasis is often accompanied by a fungal infection.
- To unequivocally exclude it, it is necessary to contact a mycologist and conduct additional research.
Nail psoriasis and psoriatic arthritis:
- Nail psoriasis is a common companion of psoriatic arthritis.
- It is important to detect pathological changes in the joints as early as possible in order to start treatment on time and avoid irreversible complications and disability.
- Even if there are no external symptoms of arthritis, but nail psoriasis is detected, it is necessary to undergo an examination of the joints with ultrasound or magnetic resonance imaging.