Psoriasis is a common skin disorder. Research indicates it affects around 3% of the population and both sexes are equally represented. There are no significant racial difference either. It can affect individuals of any age, although the symptoms most commonly appear between the age of 15 and 30.
Psoriasis is a chronic immune disorder which affects 3% of the population. It is a typical immune disease. Psoriasis affects the entire skin cell cycle, making the skin cells divide at a higher rate as they normally do. Many risk factors for the appearance of this disease are known, the most important being the family history of the disease. This indicates an important genetic component to the disease.
The disease affects the normal cell cycle of the skin cells, causing them to divide more rapidly than in disease-free people. In a healthy body, special cells called the T lymphocytes defend the body against foreign invaders such as the viruses and bacteria. In the case of psoriasis, T-lymphocytes turn against the body's own skin cells and attack them, similarly as they do when presented with foreign invaders. Dead skin cells and lymphocytes accumulate which gives the skin its characteristic appearance.
The exact cause of the phenomenon of the immune reaction against the body's own cells has not yet been elucidated. However, many factors that increase the risk of disease appearance are known and include infections (influenza), dermal injuries such as cuts or severe sunburns, stress, cold climate, smoking, alcohol abuse as well as certain medications (lithium).
The most important risk factor is family history of disease which shows that psoriasis has a strong genetic basis. As many as a 1/3 of psoriasis patients have a relative with the same disease.
Psoriasis is a chronic disease. It may appear cyclically and last for several weeks or months. Remission follows with almost unnoticeable signs and symptoms. The most common feature of disease is islands of red skin with silvery scales on top of it. In these areas, the skin is dry and chapped. The islands of diseased skin may be small and rare, or they may involve large skin areas. The diseased area may itch, feel warm or be painful. There are also changes in nails with them being clubbed and raised. Often joints are affected as well (psoriatic arthritis).
For diagnostic purposes, a thorough physical exam and a detailed patient history usually suffice. To unequivocally confirm the diagnosis, however, a skin sample may be removed for biopsy to determine the exact type of disease and rule out other skin disorders.
Regular skin care is essential. We recommend oil baths and special skin creams and ointments. Patients should lead as healthy a lifestyle as possible. We discourage consumption of fatty foods, especially consumption of fats of animal origin as well as alcohol and smoking. Patients should enjoy a wide variety of food products, rich in vitamins, and consume a lot of fruits and vegetables as well as fats in the form of omega fatty acids and olive oil. Taking lecithin and selenium supplements is also encouraged. Enough liquid should be taken in, especially the non-carbonated drinks.
Moderate natural sunbathing is most beneficial to most patients. Exposure to UV light should be moderate and general preventive measures should be taken. Patients with extensive psoriasis require irradiation of larger skin areas; such treatment is carried out under medical supervision. Sojourn in some natural spas has a very beneficial effect, characterised by a synergistic effect of many factors such as a friendly climate, relaxation, adequate nutrition, thermal mineral baths (balneotherapy), regular use of remedial and conditioning ointments and also irradiation.
Since the cause of psoriasis is unknown, it cannot be totally cured. It is important that the patient would be followed by a dermatologist for only a specialist can determine the most suitable treatment modality. The purpose of the therapy is to remove foci of diseased skin, i.e. scales and skin redness, as well as to maintain the best possible condition of the treated skin. When larger skin areas or joints are affected, hospitalisation is required.
There are three treatment modalities for psoriasis: topical ointments, irradiation and, in severe cases, medications in the form of tablets, injections and infusions.
Topical ointments contain substances that act to dissolve the scales (salicylic acid), anti-inflammatory substances (tar and its derivatives) or immunosuppressants (anthralin, corticosteroids). Lately, tacrolimus, pimecrolimus, ascomycin and substances similar to Vitamin D (calcitriol and calcipotriol) and Vitamin A (retinoids—tazarotene) have been found to hold much promise.
In ultraviolet light irradiation, selective ultraviolet phototherapy (SUP) with UVA, photochemotherapy (PUVA) as well as narrow-band UVB phototherapy, are used. A large number of irradiation sessions are required, generally from 25 to 35. High-energy lasers are used to irradiate dilated and elongated dermal capillaries. In the last two years, laser systems that generate high-energy UVB light of specific wavelengths have become available. Their huge advantage is the ability to irradiate only the disease foci and not the healthy skin. In addition, a combination of various therapies such as taking retinoids in combination with the photo-chemotherapy in the form of the standard irradiation or PUVA-baths may be successful.
In more severe cases, hospitalisation is required and treatment is with medications in the form of pills, injections or infusions. To that effect, retinoids (acitretin), immunosuppressant (cyclosporine) and, in selected cases, also cytostatic drugs (methotrexate) are used. Biological immuno-modulatory drugs such as alefacept, efalizumab, etanercept and infliximab in the form of subcutaneous, intravenous and intramuscular injections hold promise especially for patients who are unresponsive to standard drugs and have an associated psoriatic arthritis.