Psoriasis is an inflammatory skin condition in which an increased production of cells results in red, flaky, crusty plaques, covered with silvery scales. These mostly occur on elbows, knees, scalp and lower back and can be itchy or sore.
Skin cells normally have a life cycle of 3-4 weeks but in the case of psoriasis, the cycle tends to be 3-7 days, causing the over-production. It varies in severity and is characterised by periods in which there are no symptoms or only mild ones. Although the condition is not fully understood, it is thought to be linked to the immune system.
There are different types of psoriasis. Guttate psoriasis affects the body in a raindrop pattern and occurs mainly on the torso. Plaque psoriasis is the more typical thick, scaly type and there is a form that just affects the nails. To confirm the diagnosis of psoriasis, and to rule out other skin disorders, a biopsy can be performed.
Life events such as stress, pregnancy or illness can bring on an attack of psoriasis. In particular, injuries to the skin and throat infections, as well as the use of certain medications, are sometimes linked to flare ups.
Initially, patients would be educated on how to look after their skin and started on topical treatments, with regular moisturisers in the form of creams and ointments. Treatment with vitamin D analogues can also be undertaken and this can sometimes be combined with topical steroids to help treat the skin and reduce the thickness of the affected area.
If the plaques are thick and fairly widespread, another option is PUVA (Psoralen with UVA) light treatment. Psoralen can be administered as a tablet or as a bath solution and in both cases interacts with ultraviolet light to treat psoriasis and other skin conditions. If the psoriasis is widespread but not very thick, narrow band UVB, which does not penetrate as deeply into the skin, is used to treat it.
Systemic regimes are designed to offer longer term control of persistent psoriasis. Examples of these are Cyclosporine, (which normally involves a course lasting from six to a maximum of twelve months) and Acitretin or Methotrexate. These are particularly applicable for patients who have suffered for many years from psoriasis and need ongoing treatment. These treatments are designed to manipulate the immune system in order to reduce the inflammatory markers in the body.
If certain criteria are met and if systemic treatment has not had the desired effect, patients may be offered biological injections. These are specifically designed to mimic chemicals naturally found in the body and to correct any deficiency in them (as insulin does in the case of diabetes).