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).onikot- nail,dys- violation,trophy- food).
From this article, you will learn about the causes of the development of psoriasis of the nails, its symptoms, which do not always show without a doubt the correct diagnosis, as well as dangerous misunderstandings about this form of the disease.
Note.There are many pictures in the article that can scare an unprepared reader.
Where do nails grow?
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 accuracy and sensitivity when working with small objects, can be an attack or defense weapon, and finally, with the help of itchy nails. Second, the aesthetic or cosmetic function of the nails is also important, especially for women.
Nails are formed by the outer layer of the skin - the epidermis. The nail apparatus includes:
- nail plate - directly 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 base of the nail plate,
- eponychium - a nail roller that protects the matrix from above from damage,
- nail bed - located under the nail plate and is responsible for its adhesion to the phalanx of the fingernails,
- hyponychium - the transition area between the nail bed and the skin of the fingertip.
Causes and mechanism of development of nail psoriasis
In its course - with periodic exacerbations and remissions - psoriasis on the nails resembles a vulgar form of the disease.
It is believed that nail psoriasis develops for the same reasons and in the same pattern as typical psoriatic outbreaks. Among these reasons, external and internal factors are distinguished.
The main internal factor is genetic predisposition. External causes are numerous and include, for example, injuries, poor diet, intoxication (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:
- Provocative 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 significantly accelerated and their maturation is disrupted.
- There are characteristic symptoms of psoriasis on the nails.
Also, the cause of psoriasis of the nails can be considered as a result of the body’s inability to adapt to adverse environmental conditions. According to this view, the main cause of psoriasis is an evolutionary alien habitat.
Consequently, this evolutionary approach considers as direct causes of unhealthy diet, lack of sun and clean water, excess toxins, lack of normal physical activity, sleep disturbances and chronic stress.
Nail psoriasis and psoriatic arthritis are linked
The link between nail damage and psoriatic arthritis has been known for a long time.
Based on observations, scientists have found that psoriatic arthritis is associated with 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), attempted to explain this connection beyond the concept of immune inflammation.
In their opinion, the fact is that the knuckle of the finger is placed 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 in the nearest nail.
This is why psoriatic arthritis is associated with nail damage so often.
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Thus, the symptoms of nail psoriasis are often indicative of psoriatic arthritis.
Let us now look at the main myths that accompany this disease, and how dangerous they are.
Myth 1: Nail psoriasis is rare.
Not really. Apparently, with psoriasis, nails suffer very often.
According to various sources, nail psoriasis occurs in the range of 6% to 82% of cases of psoriasis vulgaris. Such a wide prevalence in assessing the prevalence of this pathology is explained by the problems in its accounting. Medical statistics record visits to doctors primarily by patients with a vulgar form, and attention is paid to nails in second place. In scientific research, cases of nail psoriasis are also commonly studied only in addition to the main object of interest - psoriasis with skin lesions.
However, a number of publications say so
up to 80-90% of patients with psoriasis vulgaris reported recurrent nail damage.
And also that nail psoriasis occurs in 90% of patients with psoriatic arthritis and scalp psoriasis.
It should be noted that usually adults 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 this is a variant of the norm or a consequence of trauma, or they simply do not notice it because of the mild severity of the symptoms.
Myth 2: Recognizing nail psoriasis from symptoms is easy
In fact, not always. The fact is that
the nail is able to respond to various diseases with only a limited number of symptoms. Therefore, the manifestations of different diseases on the nails may look the same.
Of course, psoriasis of the nails can be suspected if the patient has severe symptoms of psoriasis vulgaris. However, nail lesions can be small compared to skin lesions and can easily be 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.
And 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 may be completely absent.
How nail psoriasis looks depends on the place of origin of the pathological changes - in the matrix or in the nail bed.
The source of the symptoms - the matrix or the bed - is important to consider when choosing a treatment. Therefore, it is necessary to determine correctly.
Symptoms that come from the nail matrix are:
- big toe symptom,
- spots and white spots (leukonychia),
- red dots in the hole,
- crushed nails.
Although the cause of these symptoms is at the matrix level, as the nail grows, pathological changes appear on the nail plate.
The symptoms, the cause of which is in the nail bed, are:
- nail detachment (onycholysis),
- longitudinal hemorrhage,
- subungual hyperkeratosis,
- symptom of an oil stain.
Next, we will dwell on each symptom separately. And let’s start with the manifestations emanating from the matrix.
Symptom of the thumb
The symptom of a finger appears on the surface of the nail plate with holes or pits, which look like depressions in a finger.
Such defects occur mainly on the nails of the hands, but they rarely appear on the feet. As the nail grows, the pits move from folding the nail to the edge of the nail plate.
The pits in nail psoriasis are usually deep, large and chaotic. They arise due to the weakening of loose groups of cells from the nail surface, in which division and keratinization are impaired.
The more severe the psoriasis, the more often the finger symptoms appear.
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, with a fungal infection.
Counting the total number of holes in all the nails will help to make the 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.
With leukonychia (from Greek).leukos- white andonikot- nail), in contrast to the superficial pits in the finger symptoms, 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 comes from the reflection of light from freely placed bundles of cells.
However, some studies suggest that leukonykia is so common in healthy people that it is not a distinguishing symptom of psoriasis. For example, a manicure damage can cause leukonychia.
Crushed nails
When superficial pits (finger symptoms) and deep areas of leukonychia (white spots) join, the nails begin to crumble.
Typically, nail biting occurs 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 collapse completely and fall off.
Red dots at the base of the nails
Apparently, red spots in the hole area and its general redness occur due to an increase in blood flow to the vessels under the nail.
Also, red spots in the hole are formed due to a violation of the structure of the nail plate itself: it becomes more transparent and thin. And because of this, firstly, the vessels become more visible, and secondly, the thinner nail plate puts less pressure on the vessels beneath it, and they are more filled with blood.
Thinning of the nail plate can also cause redness of the entire nail bed.
Nail detachment (onycholysis)
Now let us consider the symptoms, the source of which is the nail bed.
Onycholysis is the separation of the nail plate from the bed due to the accumulation of cells under the nail with impaired separation and keratinization.
Onycholysis itself (from the Greek.onikot- nail andsolution- separation) is not necessarily a sign of psoriasis and may develop, for example, as a result of a nail injury.
Initially, the loss of contact between the nail and the bed occurs in the area of hyponia - along the outer edge of the nail plate. Onycholysis then spreads to the fold of the nails in the form of a semicircular line. The flowering area becomes white due to the accumulation of air under the nail.
A reddish border (scientific erythema) along the edge of the onycholysis, which is usually visible on the fingers, is characteristic of psoriasis and helps to make the correct diagnosis.
With prolonged onycholysis, the nail bed loses its properties and new growing nails will most likely not be able to join it normally. Therefore, even with a complete renewal of the nail plate, onycholysis often persists.
Due to the fact that onycholysis facilitates the penetration of bacteria and fungi, the infection can coalesce. This sometimes leads to nail stain. For example, a green color can occur when bacteria come togetherPseudomonas aeruginosa(Pseudomonas aeruginosa) and others.
Longitudinal subungual hemorrhage
Longitudinal subungual hemorrhages occur in the nail bed and appear as dark red streaks 1-3 mm long.
Increased blood flow and edema in the area of inflammation of the nail bed lead to rupture of capillaries, which is manifested in the form of such hemorrhages.
Due to the peculiarities of the blood supply, most hemorrhages occur closer to the free edge of the nail - in the area of hyponia.
Subungual hyperkeratosis
Subungual hyperkeratosis is an accumulation of dead cells beneath the outer part of the nail plate.
With psoriasis, subungual hyperkeratosis (from Greek).hyper- too much andkeras- horn) is usually silvery white, but may also be yellow. And when the infection joins, it can become, for example, green or brown.
The more the nail rises above the nail bed, the higher the activity of the pathological process.
On the fingers, subungual hyperkeratosis is usually manifested by loose layers under the nail plate. On the foot, these masses are firmly joined by a thick nail.
Also, psoriasis with toenail lesions is characterized by a combination of subungual hyperkeratosis with onycholysis (splitting of the nail).
Symptom of oil stain
The symptom of an oil stain appears under the nail plate in pieces of yellow-red color (salmon).
They rise to the nail bed closer to the nail fold and move towards the edge of the nail as it grows.
The cause of this symptom is inflammation of the nail bed with enlargement of capillaries and an accumulation of cells involved in inflammation, as well as cells with impaired 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, near the onycholysis area.
Myth 3: Nail psoriasis is just a cosmetic problem.
In fact this is not true. Although over 90% of patients report ugly nails 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% - for problems in daily activities,
- 56% - for difficulties at home and
- 48% - for difficulty at work.
Therefore, it is very important to establish the correct diagnosis and start treatment as soon as possible, as 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 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 fact that the joints of the fingers and toes are affected, but also the joints of the back and pelvic bones can be involved.
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 make sure that all the joints are in order.
And then regularly monitor the condition of the joints. Otherwise, psoriatic arthritis can be easily lost! A late diagnosis will lead to late treatment and, as a result, irreversible joint damage and disability.
Therefore, if the doctor has not ordered research on insurance, citing the absence of obvious signs of arthritis, you should contact the clinic itself and undergo, for example, an ultrasound scan on a paid basis.
How to diagnose nail psoriasis
It is important to be able to recognize many of the symptoms of nail psoriasis, which we described above, as they help in establishing the correct diagnosis. But since the characteristic nail changes of psoriasis can also occur in other diseases, it can be difficult to make an accurate diagnosis right away.
In this case, the presence of several symptoms at the same time on different nails can help in the diagnosis.
Important signs of psoriasis on nails are:
- a symptom of the thumb: more than 20 holes in all fingernails indicate the possibility of psoriasis and more than 60 holes confirm the diagnosis of psoriasis,
- nail detachment (onycholysis) with a reddish border around the lip,
- oil stains (salmon) on the nail bed.
Difficulties in diagnosing nail psoriasis from a single symptom
It is especially difficult to diagnose nail psoriasis if it appears with only one symptom.
For example, if only onycholysis in the hands or only subungual hyperkeratosis in the arms and / or legs is manifested.
The only method to make a reliable diagnosis in isolated onycholysis (nail detachment) is probably the study of hyponics using a special microscope - a dermatoscope.
For this, a high magnification video dermatoscope is used. Please note that the hand dermatoscope does not provide the required magnification. What is needed is a video dermatoscope with a magnification of at least 40 times. Then the dilated capillary buds characteristic of psoriasis become visible.
With isolated subungual hyperkeratosis, the likelihood of psoriasis is high if the accumulation of scales under the nail is white-silver in color, 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 splitting) in psoriasis may resemble the manifestations of a fungal infection. Therefore, it can be difficult to perform differential diagnosis, that is, to identify 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 in the toes and is mainly characteristic of elderly patients.
Also, with a fungal infection, one or both nails on the big toes are often affected. In psoriasis, as a rule, several nails are affected simultaneously.
The following symptoms speak in favor of psoriasis:
- oil stains and / or a symptom of the thumb on the fingernails,
- signs of psoriasis on the scalp and / or large folds of skin,
- periodic remission and worsening of nail damage.
In favor of onychomycosis they say:
- longitudinal lines on the affected nail,
- detection of fungi during examination under a microscope of a scratch treated with potassium hydroxide by an affected nail (KOH test),
- positive culture for fungi.
In general, based only on external manifestations, it is impossible to completely rule out fungal nail infection in patients with psoriasis.
It should also be remembered that a fungal infection can cause the Kebner phenomenon on the nail and surrounding skin, resulting in psoriasis symptoms. So anyway
it is helpful to go to a mycologist and get tested for the fungus and, if found, start antifungal therapy.
Important findings and what to do
Let us summarize important information about nail psoriasis and its symptoms.
Diagnostic features:
- Nail psoriasis is very common but often gets lost.
- Manifestations of nail psoriasis can be minor, so even experts often do not pay attention to it.
- In 5% of cases, nail damage may be the only symptom of the initial psoriasis.
- The manifestations of different diseases in the nails may look the same, which further complicates the diagnosis.
The main manifestations of nail psoriasis:
- a symptom of a toe - pits in the nail,
- white dots,
- crushed nails
- red dots in the hole area,
- nail detachment,
- longitudinal subungual hemorrhage,
- subungual hyperkeratosis - loose groups under the nail,
- symptom of an oil stain.
Psoriasis and fungus:
- Often, nail psoriasis is accompanied by a fungal infection.
- To rule it out unequivocally, it is necessary to contact a mycologist and do additional research.
Nail psoriasis and psoriatic arthritis:
- Nail psoriasis is a common accompaniment of psoriatic arthritis.
- It is important to detect pathological changes in the joints as soon as possible in order to start treatment on time and avoid complications and irreversible disability.
- Even if there are no external symptoms of arthritis but psoriasis of the nails is detected, it is necessary to undergo an examination of the joints using ultrasound or MRI.