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TapioRantanen

Psoriasis

Essentials

  • According to a report published by the WHO in 2016, the prevalence of psoriasis in different countries ranges between0.09% and 11.4% http://apps.who.int/iris/bitstream/handle/10665/204417/9789241565189_eng.pdf. It is rare in young children (picture 1).
    • There are two peaks of onset, and both have a different genetic background.
      • Early onset psoriasis develops before the age of 40 years, is often familial and, on average, more severe than the late onset type.
    • The triggering factor in early onset psoriasis, particularly in guttate psoriasis, is often a streptococcal infection, whereas late onset psoriasis is highly associated with preceding stressful life events.
    • Obesity, smoking and excessive alcohol consumption are other known risk factors.
  • Psoriasis is a chronic, disfiguring and stigmatising disease which may adversely affect the patient's self image and quality of life. It may be associated with significant anxiety and depression.
  • Psoriasis is associated with e.g. an increased risk of obesity, diabetes and dyslipidaemia as well as hypertension and other cardiovascular diseases. These often go undiagnosed or without adequate treatment.
  • A considerable share of the patients will over the years develop psoriatic arthritis Psoriatic Arthritis, the early diagnosis and treatment of which may reduce the risk of permanent joint damage.

Clinical features

  • The diagnosis of psoriasis is based on the clinical picture.
    • In special cases, a biopsy specimen Skin Biopsy: Indications and Technique may be beneficial. The specimen should be taken from the middle of an untreated plaque using a 4-6 mm biopsy punch.
  • Plaque psoriasis (nummular psoriasis, psoriasis vulgaris; picture 2) is the most common type (about 90% of all cases). The characteristic plaques are symptomatic and symmetrically distributed on the elbows (pictures 3 4), knees (picture 5), legs, lower back (picture 6) and scalp (pictures 7 8 9).
    • The plaques are sharply demarcated, red and thickened patches with a diameter of no less than 0.5 cm (pictures 10 11). The plaques are covered with a layer of silvery scales, the thickness of which is patient specific and varies according to treatment.
      • Gentle scraping of the scales reveals minute capillary bleeding points (Auspitz sign; picture 12).
      • Plaque psoriasis is further divided into large plaque psoriasis (plaques over 3 cm, picture 2) and small plaque psoriasis (plaques less than 3 cm, picture 13).
    • When the plaques are localised within apposed skin surfaces - submammary region, navel (picture 14), groin (pictures 15 16), gluteal cleft (picture 17), axillae (picture 18) - scaling is uncommon (flexural psoriasis, psoriasis inversa).
  • Guttate psoriasis is a widely distributed skin eruption (picture 19); typically in a young person after streptococcal tonsillitis. The condition usually resolves itself, but it may flare up later with small individual spots or it may develop into plaque psoriasis.
  • Pustular forms of psoriasis are rare. These include acral psoriasis (pictures 20 21), palmoplantar and generalised psoriasis (picture 22), and erythrodermic psoriasis, which involves the entire skin (pictures 23 24).
  • The fingernail changes, including pitting (picture 25), oily macules (pictures 26 27), distal onycholysis (picture 28), subungual hyperkeratosis (picture 29) and crumbling of the nail plate, are often useful in differential diagnosis. They are commonly seen in psoriatic arthritis Psoriatic Arthritis.

Differential diagnosis

Scalp

  • In seborrhoeic dermatitis Seborrhoeic Dermatitis in the Adult (picture 30) the flakes are thinner, "greasier" and the condition responds better to treatment. It is often difficult to differentiate seborrhoeic dermatitis from psoriasis unless other skin areas offer additional information.
  • Fungal infection of the scalp Dermatomycoses is uncommon in Western populations. It mostly affects children. This diagnosis can be excluded by a negative fungal culture.
  • Neurodermatitis of the neck (lichen simplex nuchae) 31 is characterised by an isolated, itchy plaque covered with thin scales.

Flexures with apposed skin surfaces

  • Seborrhoeic dermatitis Seborrhoeic Dermatitis in the Adult (picture 32) may resemble flexural psoriasis. Examine other skin areas. It is not always necessary to differentiate between these two conditions, as the treatment is the same.
  • Fungal infection (tinea, see Dermatomycoses) in the groin may resemble psoriasis; however, it usually heals in the centre and expands peripherally. Positive fungal culture is diagnostic.
  • Candidiasis presents as a moist area of erythema with outlying "satellite eruptions". Candidiasis diagnosis may be confirmed with a culture.
  • Erythrasma is a macular brown area with few symptoms, most often found in the armpit or groin. It is caused by an overgrowth of diphtheroids in the normal skin flora. These areas fluoresce coral pink under long-wave ultraviolet radiation (Wood's light).

Palms, soles of feet

  • Pictures 33 and 34
  • It may be difficult to differentiate hyperkeratotic eczema of the palms and palmoplantar pustulosis (pictures 35 36) from psoriasis. Examine the entire skin.
  • Fungal infection Dermatomycoses is usually unilateral and is easily diagnosed by direct microscopy from a good quality specimen.

Treatment Antistreptococcal Interventions for Guttate and Chronic Plaque Psoriasis, Interventions for Nail Psoriasis

  • Treatment should aim at minimizing symptoms and improving any illness-induced impairment of the patient's quality of life.
    • Psoriasis may be associated with anxiety or depression as well as other associated diseases requiring further management.
  • Current treatment practices are listed in table T1. The treatments are divided into topical treatment, phototherapy and systemic treatment, and they are provided for the different levels of health care.
  • The choice of treatment (picture 37) depends on
    • the psoriasis subtype and the effect it has on the patient's life
    • the extent, severity and location of the lesions
    • the availability, feasibility and cost of treatment modalities
    • the patient's age and life situation as well as response to earlier treatment and the possible presence of comorbidities.
  • Psoriasis is a chronic condition and, in addition to the acute phase treatment, a long-term treatment plan must be considered.
  • Consideration should also be given to diseases and risks associated with psoriasis (e.g. metabolic syndrome and associated disorders) as well as to lifestyles with a detrimental effect on psoriasis (alcohol consumption, smoking). The total cardiovascular risk should be assessed from time to time (e.g. using the SCORE risk chart http://www.escardio.org/communities/EACPR/toolbox/health-professionals/Pages/SCORE-Risk-Charts.aspx) in all patients receiving phototherapy or systemic medication and in patients over 40 years of age.

Classification of psoriasis treatments

Topical treatmentPhototherapySystemic treatment
* = No licensed indication (i.e. not eligible for reimbursement in some countries)
Self-care
Emollients
Keratolytic agents
Dandruff shampoos
Hydrocortisone
Occlusive dressings
Natural sunlight
Home UVB light box
General practitioner/ primary health care
Vitamin D3 derivatives (calcipotriol, calcitriol)
Glucocorticoids
Combination products
Adjustment training courses with emphasis on heliotherapy
UVB
Specialist / specialised care
Calcineurin inhibitors* (tacrolimus, pimecrolimus)
UVB, broadband
UVB, narrowband
PUVA, topical
Primary:
Acitretin
Methotrexate
Ciclosporin
Secondary:
Apremilast
Dimethyl fumarate
Biologicals

Topical treatment Combination Regimens of Topical Calcipotriene in Chronic Plaque Psoriasis

  • Topical treatment is the main form of treatment available for a general practitioner, and in most cases it is all that is needed for psoriasis management.
  • Ointments and creams may also enhance the effect of other treatment regimes.

Plaque psoriasis

Plaque psoriasis in specific areas

  • Scalp psoriasis (pictures 38 39) is treated with frequent shampooing (periodically, using an anti-dandruff shampoo). If necessary, salicylic acid exfoliation may be used initially followed by a glucocorticoid solution or a combined preparation.
    • A layer of scales will prevent the penetration of medicated preparations.
    • Salicylic acid is often used as a 5-10% mixture (prepared in the pharmacy) in a cream, castor oil or macrogol ointment base.
  • Psoriasis on the face may be treated by
  • Flexural psoriasis may be managed with the same preparations as those used on the face. Some patients may also tolerate vitamin D (calcitriol) ointment in flexural areas.
  • The treatment of psoriasis on the palms and the soles of the feet (pictures 40 34 41) consists of the above mentioned medicines used in plaque psoriasis. To treat hyperkeratosis, salicylic acid may be mixed up to 20% potency. In the most severe cases, a systemic drug (acitretin, methotrexate) is needed.

Guttate psoriasis

  • If guttate psoriasis is not very extensive, the topical treatment forms described for plaque psoriasis may be used, particularly topical glucocorticoids.
    • UVB phototherapy is the treatment of choice for extensive guttate psoriasis.

Pustular psoriasis and erythrodermic psoriasis

  • The principal treatment regime consists of systemic drugs, which may be supplemented with emollients and topical glucocorticoids.

Phototherapy Phototherapy for Psoriasis

  • Phototherapy http://www.dynamed.com/condition/psoriasis#PHOTOTHERAPY may be used in extensive guttate and plaque psoriasis in persons whose skin tolerates exposure to the sun and tans easily.
  • Certain photosensitising medications may be a contraindication for phototherapy.
  • Spending time in natural sunlight will alleviate psoriasis.
    • To achieve a good treatment response, the daily exposure to sunlight must continue for 3 weeks.
    • Adjustment training courses with emphasis on heliotherapy may be covered by national health insurance schemes. The insurance cover varies from country to country. Lost earnings may also be reimbursable.
  • Ultraviolet B radiation (UVB treatment). The prescribing physician must be familiar with the patient's particular skin type as well as the radiation spectrum and dose rate emitted by the phototherapy equipment. Moreover, the amount of radiation exposure and the cumulative dose must be recorded. If the treatment has benefited the patient, a general practitioner may prescribe repeat sessions.
    • The conventional broadband UVB therapy is effective in guttate psoriasis and in mild plaque psoriasis. The therapy is not associated with an increased cancer risk.
      • It may be possible to install a phototherapy unit at the patient's home. Home UVB phototherapy is a very cost-effective treatment modality.
    • Narrowband UVB therapy (311-313 nm) is more effective than broadband therapy and is the phototherapy of choice in psoriasis.
      • The treatment efficacy is as good as, or better than, that achieved with bath-PUVA (using topical psoralens).
      • So far there is inadequate data as regards the risks of long-term use.
  • In PUVA therapy (combining a psoralen and ultraviolet A) Systemic Treatments for Severe Psoriasis, the patient's skin is sensitised to light with a psoralen, which is administered either topically (bath-PUVA or cream-PUVA) or by mouth (oral-PUVA). PUVA therapies are nowadays only rarely used and they may be prescribed by a specialist physician only.

Systemic drug therapy

Referral to specialist

  • Children affected by psoriasis (pictures 10 1) and patients with psoriasis not responding to usual treatment modalities
  • A young person with recently developed psoriasis that affects the skin extensively or in visible areas of the skin.
  • Suspicion of excessive glucocorticoid use (pictures 42 43)
  • An experienced dermatologist can be more helpful in the diagnosis of problematic psoriasis than sending off a skin biopsy.

References

Evidence Summaries ⬆