Psoriasis (scaly psoriasis) is a chronic inflammatory skin disease characterised by a rash of reddish plaques covered with silver scales. It is a relatively common skin disorder – it is estimated that up to 8.5% of the general population is affected by psoriasis. It has been observed that psoriasis is slightly less common in children than in adults, and that gender has no influence on the onset of the disease.
Factors that increase the likelihood of developing psoriasis (or provoke an exacerbation):
- Genetic factors. Around 40% of people with psoriasis have first-degree relatives who also have the disease.
- Use of certain medications, e.g. beta-blockers, lithium, antimalarials, etc.
- Infections, especially those caused by streptococci
- Alcohol consumption
- Vitamin D deficiency
Mechanism of disease
In the past, it was thought that scaly skin was a skin disease caused by an accelerated proliferation of keratinocytes. It is now known that the mechanism of psoriasis is closely linked to dysregulation of the immune system, where T lymphocytes and other immune cells play an important role. The characteristic psoriasis rashes are caused by:
- Accelerated proliferation and impaired differentiation of epidermal cells
- Infiltration of inflammatory cells
- Dilation of blood vessels
In comparison, the cell cycle of a healthy epidermal cell lasts about 28 days, while that of a psoriatic skin lesion lasts only 5-6 days.
Symptoms of psoriasis
The main forms of psoriasis:
- Plaque psoriasis is the most common form of psoriasis, accounting for up to 79% of all cases. This form is characterised by a more or less symmetrical rash on the scalp, elbows and knees, but it can affect any part of the body. It forms distinct pink plaques covered with a thick layer of silver-coloured scales (scales). The size of the plaques varies from 1 to 10 cm and they may fuse together to form larger lesion areas. Patients sometimes complain of itching.
- Dropsy (most associated with infection). Characterised by a sudden onset of the disease, with small plaques and papules erupting in a short period of time. Patients often say they had a cold, sore throat, tooth repair, etc. before the onset of scaling. It is infectious diseases that provoke dropsy psoriasis. The rashes are < 1 cm and drop-shaped, hence the name psoriasis. The trunk and limbs are most affected.
- Pustular. This is the most severe form of psoriasis, sometimes even life-threatening. Pustular psoriasis (von Zumbusch) occurs suddenly, when the skin of the whole body becomes red, erupts in small pustules, the patient has a fever, general weakness, and inflammatory changes in the blood. Other forms of pustular psoriasis are acrodermatitis, characterised by the formation of pustules on the tips of the fingers, and pustulosis of the palms and soles of the hands and soles of the feet, in which the pustules are confined to the palms of the hands and soles of the feet.
- Erythrodermic. A rare form of psoriasis characterised by redness and scaling of the skin of the whole body. Patients with this form of psoriasis usually require hospital treatment.
- Wrinkles. It affects the armpits, navel, groin, behind the ears, under the breasts and other natural wrinkles on the body. Often the disease has to be differentiated from a fungal infection, as wrinkle psoriasis does not have the characteristic silver crust of dandruff.
- Nails. Nail lesions in psoriasis are caused by damage to the nail bed or growth zone. Often nail psoriasis is one of the first indicators that a patient is at increased risk for psoriatic joint damage. Characteristic symptoms of psoriatic nails include pitting of the nail plate, leukonychia (white spots), crumbling of the nail plate, the ‘oil spot’ phenomenon, and onycholysis (detachment of the nail plate).
Although psoriasis is a skin disease, recent research has established a link between psoriasis and other diseases of the internal organs, in particular:
- Cardiovascular disease
- Oncological diseases
- Diabetes mellitus
- Arterial hypertension
- Metabolic syndrome
- Inflammatory bowel disease
- Autoimmune diseases
This does not mean that all people with psoriasis will also develop the above diseases during their lifetime, but the increased risk remains. This may be due to chronic inflammation in the body, lifestyle factors or side effects of drugs used to treat psoriasis.
The course of the disease is chronic, undulating and characterised by periodic exacerbations.
How psoriasis is diagnosed
Diagnosis of the disease is not difficult. A thorough examination by a dermatologist is usually sufficient. Not only the skin is examined, but also the head and nails. Diagnosis is based on the characteristic rashes, i.e. distinct reddish plaques covered with silver-coloured scales. The suspicion of the disease is greatly strengthened by the presence of lesions on the scalp, the occiput, elbows, knees, umbilicus and nails. The disease is definitely confirmed by the so-called Dawn phenomenon, where the scales are wiped clean and spot bleeding is visible. During the consultation, it is very important to find out whether the patient is taking any medications that could provoke the onset of psoriasis. Other tests are usually not necessary to diagnose psoriasis. Skin biopsy and histological examination are only carried out when the diagnosis is uncertain.
The disease is distinguished from seborrhoeic dermatitis, monetic dermatitis, fungal infection, etc. We therefore always recommend that you consult a dermatologist for a precise diagnosis and treatment.
Treatment of psoriasis
As psoriasis is a chronic disease, it cannot be cured permanently. It is characterised by periodic flare-ups with more intensive treatment and skin support measures between flare-ups.
Treatment methods are selected according to the severity of the disease, the extent of the rashes, the patient’s preferences, comorbidities, effectiveness and other individual factors.
If the disease is not widespread and sporadic plaques are observed, treatment with topical agents such as moisturising creams, keratolytics (e.g. salicylic acid ointment, which is effective in removing thick scales), and corticosteroid ointments is prescribed. This is usually enough for a mild form of the disease. Other alternatives to topical treatments include tar preparations, vitamin D analogues, etc. Each case of psoriasis is individual and the treatment is selected on a case-by-case basis. If the doctor’s instructions are carefully followed, the skin condition improves within 2 to 3 months.
When the disease is not widespread, but is slow to respond to conventional topical treatments, phototherapy or photochemotherapy (PUVA therapy) is recommended. PUVA baths or PUVA creams are used. Often, several treatment methods are combined: UV therapy, corticosteroids and other medications.
For moderate or advanced disease, phototherapy is one of the first-line treatments. Either bath PUVA or systemic PUVA is available (depending on the patient’s condition and preference). Other topical treatments such as emollients, keratolytics, etc. are also used in parallel. If the rash is slow to heal despite treatment, systemic treatment of the scaly rash should be considered, after assessing the patient’s condition and carrying out the necessary tests. For systemic treatment, methotrexate or acitretin is the first choice (again depending on the patient’s general condition, the results of tests and other individual factors). Finally, if topical medications, phototherapy and systemic medications do not work and the disease progresses, treatment of psoriasis with biological therapy is considered.
If the patient is receiving systemic treatment, this requires regular monitoring by a dermatologist and periodic blood tests.