Psoriasis is a chronic inflammatory skin disease that occurs with thickened areas (erythematous plaques) covered with silvery-gray scales that, in some cases, can be itchy (itchy).
Typically, the plaques are located in the elbows, knees, scalp, face, hands and feet but can also be present in other parts of the body.
Psoriasis is caused, in genetically predisposed individuals, by the interaction between the body's defense system (immune system) and environmental factors. In response to environmental factors (physical skin trauma) the immune system reacts by producing certain substances that facilitate the repair of skin damage. In susceptible individuals, these substances stimulate the lymphocytes to in turn produce factors that induce skin cells to reproduce too quickly and thus to form erythematous squamous plaques.
Psoriasis is a lifelong (chronic) and currently untreatable disease. However, there are treatments available to effectively control the ailments (symptoms) it causes.
It can arise at any age, with no difference between men and women, but usually appears for the first time between 15 and 35 years. Its diffusion in the Italian population is estimated at 2.8%, which means that about 1,500,000 Italians are affected.
Psoriasis has a cyclical pattern in which periods characterized by mild or absent disorders (symptoms) alternate with others in which the symptoms are more intense. The severity of the disease varies from person to person: in some it causes only slight irritation, in others it can significantly reduce the quality of life.
Like all diseases that affect the skin, psoriasis often causes discomfort in the affected person by prompting them to avoid social occasions that can bring out damaged areas of skin. For this reason, the quality of life can be affected and the disease can be a social problem.
Psoriasis is not a contagious or infectious disease and cannot be passed from person to person.Symptoms
There are different types of psoriasis distinguished from each other by shape and trend over time.
The most common form (80% of patients) is the vulgar psoriasis characterized by the presence of thickening of the skin (plaques) covered with silvery-gray scales. They appear preferably on the elbows, knees, scalp and lower back although they can occur anywhere else on the body.
Scaly plaques can range in size from a few centimeters to several tens of centimeters and may or may not be itchy, painful, or both.
In the case of scalp psoriasis, the plaques can be small or cover the entire surface of the head. In some cases, the plaques cause intense itching while, in others, they cause no discomfort.
Another variant is the guttate psoriasis which occurs in particular in children and adolescents, up to about 15 years of age, with small patches that can occur both on the chest and on the limbs. Usually, the guttate psoriasis appears as a result of an airway infection caused by a germ, streptococcus, which causes sore throat, pharyngitis or tonsillitis.
In about half of sufferers, psoriasis also occurs on the nails (nail psoriasis) causing the formation of transverse spots or stripes and, consequently, the loss of color (psoriatic onychopathy). Nails can also grow excessively and often separate from the underlying skin. In severe cases they can flake off.
In the inverse psoriasis there is the formation of very red and smooth spots in the skin folds such as armpits, groin, between the buttocks and under the breast. Unlike the vulgar psoriasis the flaking is very little or absent.
There inverse psoriasis it is made worse by sweating and friction on the skin and is more common in overweight people.
Another variant is the pustular psoriasis, very rare but particularly serious. It is characterized by the presence of pus-filled pustules, surrounded by red skin (skin), which can extend over the entire surface of the body. The pus is made up of white blood cells but is not caused by an infection, so the disease is not contagious.
There are multiple types of pustular psoriasis: the generalized form, or von Zumbusch's psoriasis, and the pustular psoriasis on the palms.
There von Zumbusch's psoriasis it is a rare condition in which pustules are present on most of the skin. It is accompanied by general ailments such as fever, chills and fatigue.
There palmoplantar psoriasis, as the name suggests, concerns the palms of the hands and the soles of the feet. The pustules tend to dry up taking on a brownish color followed by skin peeling. As a rule, this form of psoriasis tends to manifest itself in a cyclical manner with time intervals characterized by the presence of pustules and others in which they are absent.
Erythrodermal psoriasis, is a rare form of psoriasis that invades the entire body surface leaving very little skin free from inflammation. It can cause intense itching or burning, loss of proteins and body fluids, the onset of infections, dehydration, hypothermia and malnutrition.
In about 30% of cases, psoriasis also affects the joints; in this circumstance we speak of arthritis psoriatic, a form that causes pain, stiffness and swelling in the joints of the hands, feet, elbows, knees and ankles (Video). Psoriatic arthritis can develop slowly, with mild disorders (symptoms), or rapidly and in an aggressive form. Skin and joint manifestations do not always appear simultaneously (Video).Causes
The causes of psoriasis are not fully known. It is considered a genetic disease that can be influenced or triggered by various environmental factors. In response to environmental factors (physical skin trauma) the immune system reacts by producing certain substances that facilitate the repair of skin damage. In susceptible individuals, these substances stimulate the lymphocytes to in turn produce substances that cause the skin cells to reproduce too quickly and to form the typical thickenings (scaly plaques) of the skin.
However, the genetic predisposition is not sufficient to explain the appearance of the disease. In fact, most people become ill with psoriasis only after a triggering event. The most important are:
- physical trauma (cut, scrape, abrasions, animal bites, sun burns, tattoos)
- infections (skin infections; streptococcal infection of the airways) especially for guttate psoriasis
- abuse of nicotine
- alcohol abuse
- some medications, such as lithium, beta blockers, antimalarials, interferon, some NSAIDs (non-steroidal anti-inflammatory drugs) can aggravate the symptoms
An initial assessment (diagnosis) of the presence of the disease can already be performed by the family doctor through observation of the skin. However, it is often necessary to undergo a specialist visit to a dermatologist to be sure as the symptoms of psoriasis can be similar to those of other skin conditions.
In most cases, a clinical examination of the skin plaques is sufficient for a correct diagnosis. Instead, in other cases, histological examination of some skin tissue samples is required.
The treatments are very different based on the type and severity of the ailments and the area of the skin affected by the disease.
They can be classified into four main areas:
- topical therapies: creams and ointments to be applied directly to the skin
- phototherapies: exposure of the skin to a certain type of ultraviolet radiation
- systemic therapies: drugs administered by mouth (orally) or by injection
- natural therapies: hydrothermal treatments
Topical therapy includes both the use of substances that facilitate the removal of scales (the so-called "keratinolytics": ditranol, salicylic acid, vegetable and mineral tar), and compounds that inhibit the hyper-proliferation of keratinocytes of the epidermis and with anti-inflammatory activity (calcitriol, calcipotriol, tacalcitol, tazarotene, orthisonics, nanosilicone).
Phototherapy is based on the use of: i) narrow band radiation (UVB); ii) ultraviolet radiation type A (PUVA) with the administration of a compound (psoralen) that sensitizes the skin to this wavelength; iii) monochromatic excimer light; iv) excimer laser, which allows to treat small areas with high power emission.
Systemic treatments (for severe forms) include drugs with strong immunosuppressive and anti-inflammatory properties (but without specific action), and in particular methotrexate, cyclosporine, oral retinoids (acitretin, etretinate). The so-called biological drugs are part of the systemic therapies, administered by injection and characterized by the remarkable selectivity of action towards certain factors of the immune system (cytokines) believed to be responsible for triggering / maintaining the inflammatory mechanism and the formation of skin plaques. Some of them block the activity of TNFα (infliximab, etanercept, adalimumab), others IL12 / IL23 (ustekinumab) and IL17A (secukinumab, ixekizumab, brodalumab).
Balneotherapy, on the other hand, is a natural therapy based on the decongestant, keratolytic, antiseptic and soothing action of the thermal waters. In some cases, in order to improve its effects, balneotherapy is combined with phototherapy. This type of treatment is suitable for mild forms of psoriasis.