Psoriasis vulgaris

Psoriasis: itchy, dry, reddened skin

In this chapter, we will inform you about the most common form of psoriasis, psoriasis vulgaris, which affects about 80% of all people suffering from psoriasis. What exactly is psoriasis and on which parts of the body can it occur? What are the triggers? Will a simple home remedy or perhaps vitamin D help? Or do you need psoriasis medication to positively influence the course of the disease? Please read on.


What is psoriasis vulgaris?

The cause of psoriasis on the scalp and body

Psoriasis is a chronic inflammatory, non-contagious skin disease that is also considered a widespread disease due to its distribution. Psoriasis vulgaris is characterised by round, red, raised and sometimes itchy areas of inflammation on the skin. These are sharply defined and covered with silvery, shiny scales. Punctiform areas that bleed, a thin membrane on the damaged skin and lamellar scaling are characteristic signs. The clinical picture ranges from individual, initially inflamed, small spots to an attack on the entire skin.

The outer sides of large joints, such as the elbow or knee, are affected particularly often, but also commonly hairy parts of the head. In addition to the skin, psoriasis often affects the nails. Typical nail changes are pinhead-sized ‘retractions’ of the nail plate, also known as spotted nails. Yellowish-brown discolouration of the nail bed can also occur, resulting in so-called crumb nails and nail detachments.

In psoriasis, plaque is the term used to describe the formation of scales and inflamed, red, often itchy areas of skin. Plaques very often occur on the elbows or knees, the scalp, and the lower back. Psoriasis vulgaris usually progresses in phases, i.e. there are times when the symptoms are almost not visible or noticeable, only to reappear after a shorter or longer break.

Forms of psoriasis

Psoriasis on the face, hand, ear, foot, or eyelid

In addition to the form of psoriasis vulgaris described above, from which approx. 80% of patients suffer, there are other variants of the disease.


The body fold psoriasis (psoriasis inversa)

Bright red plaques in the mostly moist folds of the body such as the abdominal, genital and buttock folds, but also the armpits and flexures, are the external appearance of this rather rare form of psoriasis. It occurs in about 5% of patients.

Psoriasis of the scalp (psoriasis capitis)

Psoriasis that appears on the hairy scalp. The affected areas do not have to be limited to the hairy area, but can also extend a few centimetres to non-hairy skin. About half of all psoriatic patients are affected by this form, although in some cases only the scalp is affected.

Drop-shaped psoriasis (guttate psoriasis)

This form occurs most often in children or adolescents. Instead of thick plaques, this type of psoriasis comes with small, red, dot-like spots that look like drops of water scattered over the body. It is often triggered by a streptococcal infection, for example tonsillitis, and is chronic in 30 to 70% of cases.

Pustular psoriasis (psoriasis pustulosa)

In this quite rare, special form of psoriasis, pus-filled blisters (pustules) form on reddened skin. Either only the palms of the hands and soles of the feet are affected, or much less frequently, the entire body.

Nail psoriasis

Finger and toenails are often affected by psoriasis. This is referred to as nail psoriasis. The nails are affected in about 50% of psoriasis patients.

Psoriasis of the palms and soles (psoriasis palmoplantaris)

In about 10 to 15% of patients, psoriasis occurs on the palms of the hands or soles of the feet. In addition to redness and plaques, painful skin tears can also occur.

Psoriasis of the entire skin surface (psoriasis erythrodermica)

In this particularly severe form of psoriasis, more than 75% of the entire skin surface is red and inflamed. Additional symptoms such as fever and swollen lymph nodes may also occur. About 1 to 2% of patients with psoriasis are affected by this life-threatening form and must be treated immediately.

About a quarter of psoriasis patients with skin symptoms have swollen and/or inflamed joints; this is known as psoriatic arthritis, which is discussed in detail here:

Psoriatic arthritis

Where does psoriasis come from?

When skin cells grow too fast

In psoriasis vulgaris, most of the skin changes occur in the two upper layers of the skin, the epidermis and the dermis.

The epidermis of the psoriasis plaques is about four times thicker than the epidermis of healthy skin. The cause of psoriasis vulgaris is therefore an 8-fold increase in cell division. The resulting impaired growth of the horny, layer-forming skin cells means that the migration of the skin cells does not take 28 days as in healthy skin, but only about 4 days.

Many cells are thus not yet mature when they reach the upper layer of the skin, and larger accumulations of immature skin cells develop.

The inflammatory processes originate in the dermis. There, the blood vessels multiply and blood flow increases. Due to a malfunction of the immune system, more immune cells migrate into the skin in psoriasis and trigger an inflammatory reaction.

The result is a greatly accelerated growth and death of skin cells, which in turn leads to a thickening of the top layer of skin.

What triggers psoriasis?

Hereditary, triggered by stress, or psychosomatic?

Psoriasis belongs to the group of autoimmune diseases. The exact causes that lead to its development are not known. However, it is known that psoriasis is caused by a malfunction of our immune system – the defence system that has the task of recognising and destroying dangerous pathogens, foreign substances, and pollutants.

In addition to a hereditary predisposition, psoriasis can be triggered by environmental factors such as skin injuries, sunburn or a change in climate. Stressful situations or infections can also be the cause of the outbreak of psoriasis vulgaris.

Thrust trigger

Psoriasis does not occur with equal intensity. The following triggers can lead to a flare-up:

  • Acute infections: flu or cold
  • Chronic inflammation in the body
  • Stress
  • Climate factors such as dry, heated air
  • Low light during the winter months
  • Hormone fluctuations, for example during pregnancy
  • Being overweight
  • Alcohol
  • Medication

Symptoms of psoriasis vulgaris

If you suffer from itchy or dry scalp or if the itching extends to the whole body, you may have the chronic skin disease psoriasis vulgaris. Especially if the itching is caused by red patches on the skin.

What are the symptoms and the course of the disease in detail? The name psoriasis reveals two essential peculiarities of psoriasis:

  1. The mostly fine, yellowish to silvery-white scales develop because too many new cells form too quickly in the diseased areas of the skin. These scales consist of dead cell remnants that adhere firmly to each other and to the underlying cells. Cells also die in the superficial layers of healthy skin. However, their remnants adhere far less, but flake off almost imperceptibly.  
  2. Underneath the scales is the pale to strong red, more or less strongly raised lichen. A strong red border protruding above the scaly surface indicates an inflammation and thus a progression of the psoriasis. In many cases, the affected skin is very itchy.

Diagnosis of psoriasis vulgaris

What the general practitioner does not know, the dermatologist knows

In the early stages, the symptoms of common psoriasis are not clear because the characteristic scales are often missing. Therefore, it is not immediately obvious to the general practitioner, who is usually the first person to see, what exactly the skin disease is. The correct diagnosis is usually only made by a dermatologist when many similar small psoriasis lesions have formed within a few weeks or plaques up to the size of a hand have developed within months.

Treatment of psoriasis vulgaris

The best remedy for psoriasis is therapeutic diversity

Unlike with other diseases, a combination of different measures must be taken against psoriasis vulgaris in most cases. So unfortunately, it is not enough to fall back on a tried and tested home remedy. An individual therapy consisting of ointments, baths, light and the like are recommended for mild forms of psoriasis. For moderate to severe psoriasis, this is often not enough. In such cases, treatment with medication is necessary.

The goals of therapy may be achievable for each patient differently. In individual cases, this can mean that effective improvement of the scaling or alleviation of the itching is considerable progress. Particular attention is paid to the visible areas of the body because the skin changes there affect both appearance and the perceived quality of life.

What therapy options are available?

To prevent the skin from drying out, nourishing, moisturising creams, ointments or even bath additives can be helpful. Balneo-phototherapy, a combination of baths with a high salt content and phototherapeutic measures, has also proven successful. Furthermore, light therapy, climatic therapy or external application with anti-inflammatory agents are available.

In addition, internal treatment with active substances that act on the misdirected immune system is also indicated. So-called conventional drugs are considered to be well-effective for moderate to severe courses of the disease. In addition, biologics or medicines known as ‘small molecules’ can also be used to treat psoriasis1. These substances are also able to inhibit inflammatory reactions.


1 Nast A, Smith C, Spuls PI, Avila Valle G, Bata-Csörgö Z, Boonen H, De Jong E, Garcia-Doval I, Gisondi P, Kaur-Knudsen D, Mahil S, Mälkönen T, Maul JT, Mburu S, Mrowietz U, Reich K, Remenyik E, Rønholt KM, Sator PG, Schmitt-Egenolf M, Sikora M, Strömer K, Sundnes O, Trigos D, Van Der Kraaij G, Yawalkar N, Dressler C. EuroGuiDerm Guideline on the systemic treatment of Psoriasis vulgaris - Part 1: treatment and monitoring recommendations. J Eur Acad Dermatol Venereol. 2020 Nov;34(11):2461-2498