Nail psoriasis is a rather rare type of psoriasis characterized by damage to the nail plates, which, as a rule, accompanies psoriatic damage to the skin or joints, in some cases it exists as an independent disease. It is clinically manifested by a whole spectrum of nail changes – from turbidity and thimble depressions to onycholysis and trachionychia. There are no subjective feelings. The diagnosis is made on the basis of anamnesis and clinical manifestations, in difficult cases, a skin biopsy is taken near the nail. Complex treatment: correction of somatic pathology, immunity and the state of the nervous system. The main therapy is carried out according to an individual scheme under the supervision of a dermatologist.
General information
Nail psoriasis is a chronic non–infectious dermatological disease characterized by a special condition of the nail plates. It has no age, gender and seasonal differences, is non-endemic, and has a complex structure of morbidity. Nail psoriasis affects 3% of the world’s population. It is believed that 40% of cases of the disease are hereditary, and 25% are associated with other manifestations of psoriasis. In 35% of patients, nail psoriasis is a pathology of unknown genesis that occurs without skin damage or joint inflammation. According to various authors, among people suffering from psoriasis of the skin, nails are affected in 11-90% of patients. Among patients with psoriatic arthritis, the prevalence of pathology reaches 80-90%. Nail psoriasis is non-contagious and does not pose a danger to others.
Aliber was the first to draw attention to the change in nails with psoriasis, a clinical description of the pathological process on nail plates was compiled by Biett in 1853. The fact that nail damage may be the only sign of psoriasis was pointed out in 1868 by Hardy. The urgency of the problem is due to the fact that nail damage is a valuable and sometimes the only diagnostic sign of psoriasis. In addition, the disease significantly worsens the quality of life of patients and has no prospect of complete cure.
Causes
Dermatologists consider psoriatic nail damage to be a polyethological disease, giving priority in its development to a combination of immune disorders and hereditary predisposition. The tendency to psoriasis may not manifest itself for years before the accidental impact of factors that provoke pathological changes. Such factors include infections, stress, fatigue, immune disorders, hormonal imbalance, injuries, allergic reactions, temperature changes and taking certain medications. Any of the triggers of the pathological process stimulates the activity of the immune system at the cellular and humoral levels, leading to a change in the content of immunoglobulins of all classes and circulating immunocomplexes, as well as to an increase in the number of lymphocytes and phagocytic activity of segmented leukocytes. Genetic predisposition to psoriasis contributes to the faster development of pathology.
The dermis is one of the main organs of the immune system, containing all kinds of immune cells. Interference of endogenous or exogenous factors in the work of the immune system disrupts fermentation at the level of cells of the dermal layer and epidermis. There is a failure in the processes of cell proliferation and differentiation, defective cells of the epidermis multiply and grow intensively, causing thickening of the nail plates, and then their deformation. The skin responds with inflammation to the appearance of altered cells. Horn cells begin to produce interleukin, which activates lymphocytes of the thymus. T-lymphocytes independently infiltrate the epidermis and stimulate hyperproliferation of keratinocytes, closing the vicious circle formed.
Thus, the nail plate involved in the process thickens, deforms, changes consistency and color. Since the nail consists of several horny plates, the formation of “plaques” occurs due to the influx of one layer of the nail onto another as a result of the disorderly and unrestrained division of the horny matrix cells.
Classification and symptoms
There are different classifications of psoriatic lesions of the nail plates. Depending on the degree of nail lesion, psoriasis is divided into atrophic (the phenomena of thinning and lysis of the nail prevail), point (the “thimble symptom” is characteristic), hypertrophic (the phenomena of hyperkeratosis of the nail plate and the periarticular space prevail). According to the intensity of manifestations, there are three stages: the first is characterized by clouding of the nail, the appearance of dents and striations, at the second stage the color of the nail plate changes, at the third plaques appear.
There are several types of nail plate lesions in nail psoriasis. The thimble symptom is the most common form of the disease, characterized by a scattering of shallow dents up to 2 mm in diameter. Leukonychia is accompanied by loosening of the nail with the appearance of air bubbles between the layers in the form of white spots and stripes. Onycholysis is manifested by the painless separation of the nail from the tissue as a result of the corrosion of the horny plate in the area of the bed with the formation of a psoriatic rim. It is an atrophic form of nail psoriasis, it can be complete (the entire nail is separated), partial (part of the nail is separated) or central (the edge of the nail is separated in the center).
Onychomadesis is characterized by the rapid separation of the nail from the tissue without the formation of a border. The symptom of hemorrhage is accompanied by thinning of the nail plate and subcutaneous hemorrhages in the form of veins and spots. It can occur when capillaries are damaged (pink-red hue, petechiae, oil stain symptom) or larger vessels (brown-black color, in the form of elongated bruises). With trachionychia, there is a change in the texture and structure of the nail (roughness, thickening, coilonychia – a sinking of the nail center), the subcutaneous tissue is not changed.
Subcutaneous hyperkeratosis is manifested by changes in the skin of the periarticular space with the addition of a secondary infection and an unpleasant odor. Paronychia is characterized by deformation of the nail and periarticular changes (thickening of the rollers, inflammation), accompanied by generalized psoriasis. With onychogryphosis, the ingrowth of disfigured hypertrophied nail plates into the skin is revealed (treatment is only surgical).
The clinical picture of nail psoriasis directly depends on the form of the pathological process, but there are also general manifestations of the disease. With the development of psoriasis of nails, the surface of the horny plates becomes cloudy, becomes uneven, dents appear on it (either small, scattered randomly, or large, located in the center). The nail changes color, acquires a yellowish or grayish tint. Its surface is deformed, becomes convex, undulating. Inflammatory edges and psoriatic plaques are formed. The horny plate becomes thinner and atrophies, capillaries begin to shine through it. The nail is separated from the tissue from different sides and in different directions. Inflammation occurs in the periarticular space, the skin begins to peel off, unbearable itching appears, combs and secondary infection join. Pus with an unpleasant odor is released from under the nail when pressed.
Diagnosis and treatment
As a rule, the diagnosis of nail psoriasis does not cause difficulties. A dermatologist makes a diagnosis based on anamnesis and clinic with the obligatory exception of mycotic lesions (taking swabs-scrapings from the nail plate). In difficult cases, a biopsy of the skin near the nail or a piece of the nail (scales) is taken, histological examination is performed. Instrumental diagnostics are usually not carried out. The pathological process is differentiated with onychodystrophy, onychomycosis, follicular dyskeratosis, nest alopecia, Bowen’s disease, squamous cell carcinoma, subarticular warts, dysplastic and neoplastic processes, horny eczema, injuries.
The tactics of treating the pathological process depends on the degree of damage to the nail plates. In the mild stage, dermatologists use exclusively local therapy. Hormonal ointments and creams, dermatotropic preparations with antipruritic effect, barrier and regenerative properties are used. Ointments with vitamin A and D3, salicylic ointments, therapeutic varnishes are prescribed. If external therapy is not enough, a course of treatment with antihistamines, vitamins and mineral complexes with calcium and zinc is connected. In severe cases, retinoids and immunosuppressants are indicated. Modern therapy of nail psoriasis consists in the use of monoclonal antibodies capable of blocking provoking factors and normalizing the process of cell division, which allows achieving long-term remission. Biological modifiers of the immune response (anti-cytokine drugs) are used to correct the impaired functions of the immune system.
Bran baths and physiotherapy procedures are prescribed: magnetotherapy, phonophoresis with hormones, UHF, PUVA therapy for psoriasis, UFO, which has cytostatic and antimycotic effects. Sometimes, if other methods of treatment are ineffective, after consultation with a surgeon, the nail plate is removed under local anesthesia. Prophylactically, it is recommended to have as short nails as possible, exclude the possibility of microtrauma, wear gloves when in contact with household chemicals. You should eat vegetables and foods rich in protein. The forecast is relatively favorable.
