Palmoplantar psoriasis is a variety of pustular psoriasis that affects exclusively the skin of the palms and feet. The primary element is a bright pink papule that transforms into a plaque that occurs against the background of hyperemia of the skin surface, accompanied by itching and peeling. Plaques merge with each other, forming foci of hyperkeratosis, sometimes part of the foci begins to resolve from the center. The surface of the palms and feet loses elasticity, cracks appear, secondary infection joins. The diagnosis is made clinically with histological confirmation. In the course of treatment, external antiseptics, hormonal ointments and PUVA therapy are used.
Palmoplantar psoriasis is a chronic heterogeneous dermatosis localized in the area of the palms and soles. According to various authors, the palm-plantar form of the disease accounts for from 1.2% to 31% of all cases of psoriasis, while recently the number of patients has been steadily increasing, which increases the relevance of this dermatological pathology. Dermatosis depends on geography and race. In the northern countries, the incidence of palmoplantar psoriasis is much higher than in the southern countries: in the Far North of the United States, dermatosis is taken away by 4%, and in Mexico – only 0.11%. Along with other factors, the occurrence of dermatosis is negatively affected by bad habits, especially smoking and an atherogenic diet profile.
Dermatologists associate a genetic predisposition in the development of the disease with subpopulation features. For example, American Indians and representatives of the Negroid race practically do not suffer from this pathology, whereas the disease is detected quite often in Europeans. There are no gender and seasonal differences. The age peak of morbidity occurs at the age over 30 years and accounts for up to 15% of cases of disability from skin diseases in general. Dermatosis is not contagious, in the entire history of dermatological observations, despite the localization of the pathological process on the palms (handshakes), there has not been a single case of transmission of palmar-plantar psoriasis from a sick person to a healthy one. The disease does not spread even with blood transfusion.
Dermatosis is heterogeneous. There are exogenous and endogenous triggers of the disease. Exogenous factors include environmental temperature fluctuations, bad habits, prolonged use of medications, infections, injuries and an atherogenic nutrition profile. Endogenous factors include hereditary predisposition, weakened immunity, stress and sensitization of the body. Provoking factors trigger the mechanism of development of the pathological process. Modern dermatologists tend to consider palmoplantar psoriasis the result of a combination of several triggers.
The mechanism of the disease is not fully understood, there are several most likely theories, the main one is considered autoimmune. A defective gene, inherited and responsible for the functional activity of the immune system, becomes a trigger that stimulates the production of antibodies. Antibodies take the cells of the surface layer of the epidermis for an alien origin. By binding and destroying the cells of the stratum corneum of the skin, the autoimmune reaction that has arisen leads, on the one hand, to degenerative processes in the dermis, on the other – to compensatory rapid division of healthy epidermal cells and inflammation in the skin, which is visually manifested first by erythema, and then by the formation of papules and peeling.
The exchange theory is based on errors in the diet. The atherogenic (“fatty”) nutrition profile is a provoking factor of lipid and protein metabolism disorders. The lack of a sufficient amount of building material (proteins) and the predominance of energetically active fats leads to the synthesis of toxic polyamines in the digestive tract. Toxic compounds cause degenerative-dystrophic changes in the skin and trigger an autoimmune process.
Neuroendocrine theory suggests a different mechanism for the development of the disease. Stress and endocrine disorders lead to changes in normal innervation and trophic skin, which violates the integrity of dermal cells, stimulates T-helper activity, changes the cytokine profile with the development of inflammation, increased keratinization processes and proliferation of epidermal cells. As a result, primary elements appear on the palms and soles. At the same time, the localization of the pathological process is due exclusively to local provoking factors (injuries of the skin, exposure to ultraviolet light or pre-existing contact dermatitis).
The allergic theory boils down to the fact that when exposed to any foreign antigen, the skin, already sensitized by taking medications, sunlight, infection and temperature fluctuations, gives a super-strong response with the production of a large number of antibodies that destroy the cells of the dermis, and the development of an autoimmune reaction. Separately, one more autoimmune reaction should be mentioned, which is the result of a viral HIV infection, which leads to a change in the number of lymphocytes, which, in combination with apoptosis (controlled programmed cell death), is visually manifested by the same rashes on the skin.
In modern practical dermatology , there are three forms of the pathological process , depending on the predominance of certain primary elements:
- Vulgar (typical, papular-plaque) form, characterized by a rash of dense pink papules and plaques up to 2.5 mm in diameter with clear borders, covered with silver scales. The primary elements are tightly soldered to the underlying tissues, combined with cracks in the skin and secondary infection, which often makes it impossible to identify a diagnostic triad.
- Horny (psoriatic “corn”) form, characterized by dense yellowish corneal foci of oval shape with a diameter of up to 3 cm, poorly flaking, with a tendency to merge.
- Barber’s psoriasis (vesicular-pustular variety), the rarest form of the pathological process, manifested by the rash of single bulls with serous-purulent filling and blurred borders against the background of hyperemia of the skin. When the elements merge, large purulent areas with wetness (“purulent lakes”) appear.
Despite some differences between different forms of palmar-plantar psoriasis, common signs of dermatosis can be distinguished. On somewhat edematous and hyperemic skin in the area of the palms and soles, very small (1-1.5 mm) primary papular elements appear, transforming into plaques, which, merging, form dense foci with clear outlines. The elements practically do not rise above the level of healthy skin. Due to hyperkeratosis, cracks form on their surface, pain occurs, disrupting the ability to work and negatively affecting the quality of life of the patient. Over time, the inflammation subsides, hyperkeratosis increases, the foci turn yellow and thicken, almost completely covering the palm or sole.
Berberus psoriasis flows somewhat differently. The primary element of this form of dermatosis is a pustule, prone to fusion and the formation of large purulent foci with sterile contents. The pustules dry out and form crusts with typical psoriatic large-plate peeling. Rashes are localized on the arch of the foot and in the area of the thumb on the hands. A feature of palmoplantar psoriasis is the possible presence of single plaques on other areas of the skin.
Clinical diagnosis is performed by a dermatologist. If possible, the diagnosis is confirmed by a specific triad, revealed by scraping papules (stearin stain, terminal film, dew drops). Be sure to conduct a histological examination. In the affected areas of the skin, sharp acanthosis with papillomatosis, hyperkeratosis, cell proliferation and thinning of the upper layers of the epidermis is detected. In difficult cases, immunomorphological studies are used, which indicate the autoimmune nature of palmoplantar psoriasis.
Pathology is differentiated with lichen planus, horny and dyshydrotic eczema, neurodermatitis, pink lichen, papular syphilis, keratoderma, acrodermatitis Allopo, Andrews bacteroid, gonorrhea and arsenic hyperkeratosis and palm-plantar-oral syndrome caused by Coxsackie virus.
Treatment and prevention
Treatment of the disease is carried out under the supervision of a dermatologist. In systemic therapy, drugs are administered orally or by injection. The list of medications used includes glucocorticoids, aromatic retinoids, cytostatics, immunosuppressants and special photoactive compounds. The best results are obtained by combining PUVA therapy of psoriasis with the subsequent addition of an excimer laser. Externally, hormonal ointments are used in pure form or in combination with salicylic acid. Vitamin D3 analogues, fat-soluble vitamins are prescribed in courses of 30 days, baths with bran, a series and celandine.
In order to prevent, an anti-atherogenic nutrition profile should be observed, chocolate, coffee and alcohol (products that can provoke a relapse) should be excluded from the diet. It is necessary to make a choice in favor of a healthy lifestyle, monitor the absence of contact of the skin of the hands with provoking factors, use gloves on the farm, wear tight socks in the cold season and use open shoes in the summer. When prescribing medications, consultation with a dermatologist is mandatory. The forecast is relatively favorable.