The plates, easily removable for scratching, leaving the surface below red, easy bleeding.
The extent of involvement of the skin può vary from localized areas of a modest size (elbows, knees, scalp, and sometimes even the nail), until the involvement of the entire body surface. Can be affected by the disease, the joints, the nails and mucous membranes.
The clinical variants are numerous. The evolution is unpredictable and the disease undergoes spontaneously phases of exacerbation, improvement, and sometimes even persistent remission. Worse in the autumn, is stationary in the winter, tends to a worsening in the spring and improves in the summer (even without exposure to the sun).
psoriasis affects about 2-4% of the population, and affects indifferently men and women, but more frequently occurs in età youth. The cause is unknown although certain factors; often the disease is found in other members of the family, and this argues in favour of an aetiology of genetic type.
To better understand the pathogenetic mechanisms of psoriasis you need to briefly describe what is skin and what are its functions. Main task of the skin is to protect internal organs from dehydration, infection, injuries and temperature changes. Also, being a sensory organ, to feel the painful stimuli, tactile, pressure, heat, cold, and so on.
The skin is composed of three layers, arranged one on the other: the superficial (epidermis), middle (dermis) and deep (in the hypodermis, or subcutaneous). Without dwelling further on the layers of the più deep, we focus attention on the epidermis, the layer that is affected by this disease.
The epidermis is composed of 4-5 layers, which represent, from bottom to top, an evolution maturativa of the basal layer. In simple words, the cells (the keratinocytes) are born at the base, and multiply, and “migrate” to the surface, where they disintegrate with washing, the trauma, the rubbing of tissues or even spontaneously.
Thanks to this cycle of maturation, of a total duration of 28 days, the body surface undergoes a continuous renewal. In the elderly, the cycle is very più slow.
In contrast, in psoriasis, it is very più fast, completing in 4-5 days instead ofé in 28. In other words, we experience a remarkable increase in the production of new skin cells compared to the unchanged old ones deleted.
Cinzia Confalone – Ministerosalute.it
psoriasis skin disease
psoriasis, a general description
The causes of psoriasis
Genetics: new findings on psoriasis
symptoms of psoriasis
How to treat psoriasis
Convivere with the psoriasi
Psoriasis and life style
frequently asked Questions about psoriasis
Acne: symptoms, causes, cures and remedies
Page updated on 26/7/2006