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What is psoriasis?

Psoriasis is an that affects the skin. It is characterized by producing scaly, thickened and highly inflamed lesions that form plaques, sometimes of large size.

Plaques can appear at any point on the skin, although they most often affect areas of folds such as knees and elbows . In some cases the disease begins with involvement of the nails (nail psoriasis).


It is a disease of chronic course , with great variability in terms of the symptoms it produces and the evolution it takes in each person.

Who is affected?

Psoriasis affects both sexes equally, although it appears earlier in women. Family members of people with psoriasis are more likely than the rest to suffer from it . In these people the disease also starts at a younger age .

It has a considerable geographic distribution: it is more frequent in the countries furthest from Ecuador. Although it can appear at any age , it is more common in adults than in children.

What produces it?

The exact cause (etiology) of psoriasis is unknown. Since the genetic predisposition can not explain the pathogenesis of the disease in its entirety, a very complex multifactorial origin is suspected.

  A series of external and internal factors act on a genetically predisposed immune system. These factors behave as triggers either the initial episode, a worsening or a reappearance after an apparent remission. All this results in the alteration of the keratinization process.

What does it mean that the immune system is genetically predisposed ?

The predisposition is due to the presence of susceptibility genes and the absence of protective genes . Susceptibility genes are genes indirectly related to the disease that make the person who has them more likely to suffer from the disease .

It has been proven that there are abnormalities in the genes expressed by psoriatic cells. Specifically, those related to epithelial growth factors.

In this case, it has been related to the presence of HLA B13, B17 and B37 among others.

What are the triggers?

In the case of psoriasis, the factors that can trigger or worsen the disease are:

  • Some infections , such as those caused by Aureus or S. pyogenes , human papilloma virus or HIV, some fungi such as Candida albicans
  • Some drugs such as lithium salts, beta-blockers or some anti-inflammatories
  • The traumas. It is common to see the typical lesions of the disease in areas that receive trauma after a few days . This is called the .
  • The cold climates. In fact, the disease worsens with low temperatures and improves with heat and sun exposure.
  • It is suspected that it may be related to some hormonal factors . It has been proven that there are two peaks of maximum incidence, one at puberty and one at menopause. In addition, it improves with pregnancy and worsens after childbirth.

Pathogenesis of psoriasis

Some hypotheses suggest that when certain antigens bind to the mentioned HLA , inflammatory pathways are activated whose final result is the appearance of psoriasis plaques.

A locus (a specific position of a gene within the chromosome) of vulnerability on chromosome 17 has also been described. It is suspected that this locus may contain the gene responsible for at least some cases of the disease.

In addition, it has been proven that there are abnormalities in the genes expressed by psoriatic cells. Specifically, those related to epithelial growth factors. This causes these cells to have an abnormally high number of receptors for EFG.

Patterns of presentation of psoriasis


Psoriasis clinic

Skin lesions

The typical lesion of psoriasis is a raised, dark reddish-scaled skin plate . They can appear anywhere on the body, although they are located more frequently in areas of folds (elbows, knees). The size of the lesions is very variable.

The scratching of the lesion reveals three very characteristic signs of the disease:

  • The scratching of the plate causes the release of small whitish scales, with the appearance of candle wax. (Sign of wax stain).
  • The detachment of the scales reveals a thin transparent membrane: the Duncan-Dulckley membrane.
  • If this membrane is detached, small petechiae appear due to vascular damage. (Sign of Auspitz) This sign does not appear in the pustular or inverted forms of the disease.

In some patients, a halo of hypopigmentation may appear around the lesion, indicating regression.

Mucous lesions

They are very rare. They appear mainly on lips and penis. There is no peeling.

Nail injuries (nail psoriasis)

They are relatively frequent, as they appear in up to 50% of patients. Nail psoriasis appears more frequently on the fingernails than on the toenails.


Given the alteration of the keratinization process that characterizes the disease, the growth of the nails is also altered. The manifestations that appear in nail psoriasis depend on the affected area:

  • Dimples and depressions on the surface of the nail (piqueteado in band).
  • Whitish discoloration “in oil stain”.
  • Onycholysis: the nail separates from the nail bed.
  • Hyperkeratosis subungueal: the nail acquires the appearance of a whitish and dense mass.

Scaly and reddened lesions around the nail that end up destroying the cuticle. It is frequently associated with psoriatic arthropathy.

Psoriatic arthropathy

It is more invalidating than exclusively skin or nail lesions. It appears in 7% of patients previously diagnosed with psoriasis.


In most cases the diagnosis of psoriasis is clinical. That is, through a detailed clinical history and a good physical examination is usually enough. In case of doubt, it is advisable to perform a skin biopsy.



  • General measures: aimed at improving, even slightly, the quality of life of these patients. It includes measures such as sunbathing, bathing in the sea, leaving the lesions on the air …
  • Topical treatments: they are less effective than systemic treatments, so they are reserved for mild cases. Among all the options, the application of creams with is one of the most recommended.
  • Hyperthermia of contact . It consists in the application of long wave radio frequency pulses to an area, which is heated “from the inside”. This is achieved by applying heat in depth avoiding “external” cooling factors.
  • Application of ultraviolet radiation (UVA rays) in cases of severe psoriasis resistant to topical treatments and in psoriasis in drops.
  • Systemic treatments based on immunosuppression / immunomodulation.

Impact of psoriasis

Psoriasis has a strong impact on the socio-labor life of those who suffer from it, as well as on their mental health.

  • Many patients with psoriasis encounter difficulties in finding or maintaining work.
  • Anxiety and depression are frequent in these patients.
  • Some patients, especially those with psoriasis in the genital area, experience intimacy problems.
  • The life of a couple is not only affected on a sexual level. The limitations of the private life of these people, together with the emotional disorders cause a serious deterioration.