Psoriasis

Background

Psoriasis is a non-infectious inflammatory skin condition affecting approximately two per cent of the UK population. Recently there has been huge progress in understanding the mechanisms involved with psoriasis. Psoriasis is now known to be an immune-mediated disorder resulting in the rapid turnover of cells in the skin and the red scaly plaques seen in psoriasis.

The majority of people with psoriasis have mild disease, with the most common places affected being the elbows, knees and scalp. However, psoriasis can appear on the skin surface at any body site and be very severe.

Credits

Medical text written October 2010, Dr S McBride, Consultant Dermatologist, Royal Free NHS Trust, London, UK.

What are the symptoms?

The symptoms of psoriasis vary considerably depending on severity and the site involved. Scalp psoriasis can be itchy and flaky and sometimes sore. Psoriasis affecting skin folds such as the armpits, groin, and under the breasts is smooth, shiny red and often uncomfortable, whereas psoriasis on sites such as the elbows and knees tends to be red, scaly and itchy. Psoriasis may affect the genitals and can be both uncomfortable and embarrassing. Many people with psoriasis find that the dry scales of psoriasis drop on clothes, furniture and floors and bed linen may become blood stained and greasy from creams.

What other conditions are linked with psoriasis?

Conditions such as arthritis (see entry Arthritis (Juvenile Idiopathic)), diabetes (see entry Diabetes Mellitus), high blood pressure, metabolic syndromes (see entry Inherited Metabolic diseases), cardiovascular disease, anxiety and depression are over represented in individuals with psoriasis.

What are the causes?

Psoriasis is now thought to be caused by a combination of environmental and genetic factors. Factors which may trigger or cause a flare of psoriasis include infections (eg streptococcal throat infection), smoking, alcohol and prescription drugs (eg beta-blockers, anti-malarials and lithium). Psoriasis can also be induced at sites of injury, and psychological factors such as stress play an important role.

Psoriasis is now thought to be caused by a combination of environmental and genetic factors. Factors which may trigger or cause a flare of psoriasis include infections (eg streptococcal throat infection), smoking, alcohol and prescription drugs (eg beta-blockers, anti-malarials and lithium). Psoriasis can also be induced at sites of injury, and psychological factors such as stress play an important role.

How is it treated?

Although there is no ‘cure’ there are now many effective treatments available for psoriasis. Treatments are adapted according to the severity of the condition and the lifestyle of the individual. Mild disease is treated with topical preparations (creams and ointments). These include tar, vitamin D analogues, vitamin A analogues, steroids and combination therapies. Potent steroids are best avoided as can cause rebounds of psoriasis even if initially effective. If the response to topical therapies is not adequate a dermatologist may prescribe a course of ultraviolet (UV) light therapy.

If UV therapy is not effective or too inconvenient systemic medications (tablets) may be prescribed. Most tablets used to treat psoriasis alter the immune in some way and require regular monitoring with blood tests. Biologic medications (administered via injection or infusion) are reserved for individuals who do not respond to, or who have side effects from conventional medications.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
A total of 30 percent of individuals with psoriasis will have a first-degree relative with psoriasis. If one parent has psoriasis their offspring have a 15 per cent chance of developing psoriasis, if both parents are affected, offspring have a 75 per cent chance of developing the condition. Several different genes have been linked to psoriasis, but the possibility of gene therapy is remote.

Prenatal diagnosis
No prenatal diagnosis is possible.

Is there support?

Psoriasis Association

Helpline: 08456 760 076
Email: mail@psoriasis-association.org.uk
Website: psoriasis-association.org.uk

The Association is a Registered Charity in England and Wales No. 257414. It provides information and support to anyone affected by psoriasis or psoriatic arthritis. The Association has a dedicated website for teenagers and young adults at psoteen.org.uk.

Group details last updated March 2016.

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