What is psoriasis?

Psoriasis is a common skin disease affecting 1 in 50 people. It occurs equally in men and women. It can appear at any age. Psoriasis is a long-term condition which may come and go throughout your lifetime. It is not infectious; therefore you cannot catch psoriasis from someone else. It does not scar the skin although sometimes it can cause a temporary increase or reduction in skin colour. Although psoriasis is a long-term condition there are many effective treatments available to keep it under good control.

Psoriasis can affect the nails and the joints as well as the skin. Psoriasis, particularly moderate to severe psoriasis, is associated with an increased risk of anxiety, depression and harmful use of alcohol. Moderate to severe psoriasis increases the risk of heart disease and stroke and treatment of psoriasis may reduce this risk. Psoriasis can also be associated with diabetes, obesity, venous thromboembolism, high cholesterol and high blood pressure. Psoriasis is also associated with inflammatory bowel disease and there is a small increased risk of skin cancer.

What You should know / Frequently Ask Questions

Both inherited and environmental factors play a role in the development of psoriasis Skin affected by psoriasis is red and scaly. The outer layer of skin (the epidermis) contains skin cells which are continuously being replaced. This process normally takes between three and four weeks. In psoriasis, skin cells divide more quickly so that cells are both formed and shed in as little as three to four days. Infections, stress, damage to the skin, alcohol, and sometimes intense sunlight may trigger flares of psoriasis. Certain medications such as beta blockers (used to treat high blood pressure and angina), lithium and some tablets used to treat malaria can also trigger flare-ups of psoriasis. Suddenly stopping some steroid tablets can also trigger or worsen psoriasis. Obesity and smoking are associated with a poor response to psoriasis treatments so exercise and being the correct weight can be beneficial.

Yes, if you have a family member affected by psoriasis you are more likely to suffer from psoriasis. The way psoriasis is inherited is complex and not completely understood involving many genes.

  • Chronic plaque psoriasis is the most common type of psoriasis. Plaques of psoriasis are usually present on theknees, elbows, trunk, scalp, behind earsand between the buttocks although other areas can be involved too.
  • Guttate psoriasisconsists of small plaques of psoriasis scattered over the trunk and limbs. It can be caused by a bacteria called Streptococcus which can cause throat infections.
  • Palmoplantar psoriasis is psoriasis affecting the palms and soles. Psoriasis may appear at other sites too.
  • Pustular psoriasisis rare type of psoriasis where the plaques on the trunk and limbs are studded with tiny yellow pus filled spots. It can be localised or generalised and can flare rapidly necessitating hospital admission for treatment.
  • Erythrodermic psoriasis is an aggressive rare form of psoriasis which affects nearly all of the skin and can sometimes require hospital admission for treatment.
  • Nail psoriasis is present in about half of people with psoriasis.

The features of nail psoriasis are: 1. Pitting (indentations) and ridging of the surface of the nail; 2. Salmon pink areas of discolouration under the nail; 3. Separation of the nail plate from the nail bed; 4. Thickening and yellowing of the nails; 5. Complete nail destruction.

Treatment of psoriasis depends upon your individual circumstances. Treatment applied to the surface of your skin (topical treatment) is sufficient alone in most patients. For people with more extensive or difficult to treat psoriasis, ultraviolet light treatment (phototherapy), tablet treatment or injection treatment may be required.

  1. Topical treatments: These include creams, ointments, gels, pastes and lotions.
  2. Phototherapy: Phototherapy is ultraviolet light delivered in a controlled way to treat psoriasis. A course of treatment usually takes about 8-10 weeks and will require treatment sessions two to three times a week.
  3. Internal (systemic) treatments.
  4. Tablet options include acitretin (related to vitamin A), ciclosporin (suppresses the immune system), methotrexate (slows down the rate at which cells are dividing in psoriasis), and in some hospitals fumaric acid esters and apremilast.
  5. Injectable treatments for psoriasis include etanercept, adalimumab, infliximab, ustekinumab, secukinumab, ixekizumab and guselkumab. Other new tablet and injected treatments are being developed in clinical studies at present.