Psoriasis (psoriasis)

Psoriasis (psoriasis)
International Classification (ICD) L40.-


Psoriasis (colloquially known as psoriasis) is a benign, often chronic inflammatory disease of the skin. The cause is probably a disorder of the immune system.

The symptoms of psoriasis can be so mild that the affected person hardly notices them. In other cases, the quality of life of those affected can be severely restricted by a pronounced clinical picture. The appearance and localization of psoriasis can vary from person to person. In addition to the skin and nails, and in exceptional cases the mucous membrane, the joints can also be affected by psoriasis, which is known as psoriatic arthritis.

Psoriasis is not a contagious disease, but it can be inherited. Therefore, the risk of disease in children of affected individuals is higher than the risk in the average population. An estimated two to three percent of all Germans suffer from psoriasis. Psoriasis occurs in all age groups. Women are affected minimally less often than men.


The exact cause of psoriasis is currently unknown. Even in people who have a genetic predisposition to psoriasis, the disease does not necessarily have to break out.

In addition to the genetic predisposition, certain triggers (triggering factors) probably play a role. Examples of triggers include bacterial infections (particularly streptococcal infections), stress and the use of certain medications.

The earlier assumption that psoriasis is the result of excessive, pathological skin renewal is now considered outdated. Skin renewal is a normal process in which the cells of the epidermis migrate to the surface, where they die and subsequently become horny. In areas of skin affected by psoriasis, this process takes only three to seven days, which is much faster than in healthy areas of skin. However, the cause of psoriasis is not the excessive skin renewal itself, but a disturbance of the skin's immune system, which causes the body's own skin cells to be killed off very quickly. The excessive skin renewal is thus the consequence of the immune system disorder.

Streptococcal infection is a common trigger of psoriasis. It is assumed that due to the great similarity between certain protein structures on the surface of the bacteria and protein structures on the surface of the keratinocytes (cornification cells of the skin) in psoriasis there is a confusion of the immune system. The defence cells of the immune system therefore henceforth attack the body's own keratinocytes. The skin cells quickly grow back, but are also killed again within a short time and migrate to the skin surface as dead scaly cells. This causes the sharply demarcated areas of skin characteristic of psoriasis, with reddened skin that is heavily perfused with blood. Almost all people with psoriasis suffer from this form of psoriasis. It is technically referred to as psoriasis vulgaris.


The symptoms of psoriasis occur in episodes. Characteristic are extensive skin inflammations that manifest themselves in certain areas of the skin with severe redness and the formation of blisters or scales. The knees, elbows, scalp and areas of skin in the sacral region are frequently affected. Particular manifestations of the disease occur primarily on the palms of the feet and hands or in the form of small patches all over the body. The length of the individual attacks varies greatly - the duration ranges from a few days to several years.

In addition, a so-called psoriatic arthritis can occur. This leads to inflammatory changes in the joints and tendons, causing them to swell painfully and restricting their normal mobility.


Psoriasis can be diagnosed on the basis of the characteristic psoriatic phenomena - taking a tissue sample is not normally necessary:

  • Candle phenomenon: If one scratches with a wooden spatula over the psoriasis hearth, some loosely seated, silvery-white skin scales fall off. Visually, these resemble the scraped wax of a candle.
  • Phenomenon of the last cuticle: If theskin is scratched deeper into the psoriasis focus, a thin, lamellar cuticle can be removed at the end.
  • Spotting phenomenon / phenomenon of punctiform bleeding: After removal of the last cuticle, punctiform bleeding appears underneath.


Since psoriasis is a genetically determined disease, it is not possible to cure it according to the current state of knowledge, but only to alleviate the symptoms.

In psoriasis therapy, the following active substances, among others, are available for external application:

  • Urea: Used for the care and treatment of the affected skin areas and is used as an additive in ointments, creams or oils.
  • Salicylic acid: Is used to remove the skin scales.
  • Coal tar: Applyingcoal tar slows down cell division and relieves itching. However, as the tar substances are now suspected of promoting the development of cancer, these preparations are now only used in exceptional cases.
  • Corticoids: These active substances alleviate the symptoms by dampening the immune system and thus weakening the inflammatory reaction in the skin. Due to the side effects, however, these preparations should only be used for a short period of time and only on small areas of skin.

In addition, there are numerous alternative medical treatment approaches (e.g. acupuncture, homeopathy, traditional Chinese medicine), which according to some sufferers have brought about an improvement in the symptoms. However, there is currently no scientific evidence for an efficacy of these treatment approaches that goes beyond the placebo effect.


According to current knowledge, psoriasis cannot be cured. However, therapy can alleviate the symptoms in the long term or temporarily eliminate them completely.

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All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.
Danilo Glisic

Danilo Glisic

As a biology and mathematics student, he is passionate about writing magazine articles on current medical topics. Due to his affinity for facts, figures and data, his focus is on describing relevant clinical trial results.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.



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