Psoriasis
What is Psoriasis?
Psoriasis is a chronic skin disorder that can take many forms and varies in severity. It is most commonly manifested as well-circumscribed, inflamed patches of skin covered with silvery scales. Once the disease presents itself, usually early in adulthood, it generally recurs throughout an individual's life. Approximately 2-3% of the population suffers from psoriasis. Between 5% and 10% of psoriasis sufferers also develop an arthritic condition associated with the skin disease. Psoriasis is not contagious and many treatment modalities are available.
What causes Psoriasis?
Psoriasis has no known cause but recent research suggests that it is an auto-immune skin disorder. Scientists also suspect that heredity, illness and stress may all play a role. There is a genetic pre-disposition to developing this condition with approximately one-third of psoriatic patients reporting a family history of the disease. Often there is an identifiable "trigger factor" leading to initial activation of the disease. These factors include strep throat, skin injury, medications such as intramuscular injections or oral steroids, or vaccinations. These factors are thought to influence the immune system into over-production of skin cells. Cells in the epidermis begin dividing and multiplying rapidly, thus producing a thickened layer of skin.
Types of Psoriasis
Psoriasis presents itself in many different forms. The disease may change over time appearing on different areas of the skin, worsening and improving in a cyclical fashion. Over the course of the disease, one form may change into another form and several forms may be present at the same time in one individual.
Plaque Psoriasis – This is the most common type of psoriasis, also known as psoriasis vulgaris. It appears as inflamed, raised patches of skin covered with silvery scales made up of dead skin cells. Although plaque psoriasis may appear on any area of the body, the most commonly affected areas include scalp, trunk, knees and elbows. This form of psoriasis is generally mild to moderate in severity. Typically, plaque psoriasis is bilateral.
Inverse Psoriasis – Smooth inflamed sores, without apparent scaling, characterise this form of the disease. It most often appears in the armpit, groin area, under the breasts and in other skin folds. The lesions are easily irritated by rubbing and sweating.
Guttate Psoriasis – This type of psoriasis occurs suddenly, often following illnesses such as respiratory infections, tonsillitis or chicken pox, after administration of medications such as anti-malarial drugs or immunisations or following emotional stress or physical trauma. This form of the disease appears as small red dots of psoriatic skin on the trunk and extremities.
Nail Psoriasis – In this condition, pits of various size and shape appear in the nail. Both fingernails and toenails may be affected. The nail may become thickened and yellowed. The nails crumble easily and may become loosened and detached from the nail bed. This condition is very difficult to treat.
Scalp Psoriasis – Approximately 50% of psoriasis sufferers are affected by this condition. It appears on the scalp as reddened bumps with silvery scales.
Pustular Psoriasis – This form of the disease is characterised by a cycle of pustule formation. It begins with a reddening of the skin followed by formation of pus-containing lesions (pustules) and then scaling of the skin. It may occur only in hands and feet, or may be more widespread.
Erythrodermic Psoriasis – As its name implies, this condition involves generalised reddening of the skin and shedding of fine silvery scales, often with swelling. It can be very itchy and painful.
Psoriatic Arthritis – Between 5% and 10% of psoriasis sufferers also develop inflammation and swelling in the joints, hands and feet. Symptoms may include stiffness and pain in the affected area. In many patients, the severity of the arthritis mimics the severity of the psoriasis: when skin is more heavily involved, the arthritis is worse, and when the psoriasis improves, so does the arthritis.
Severity of the Disease
Psoriasis may also be classified as to severity of the disease from mild to moderate to severe, depending on the area of skin exhibiting the lesions. By definition, mild psoriasis affects less than 5% of the body surface, moderate psoriasis affects 5-20% of the surface and severe psoriasis describes greater than 20% involvement. For reference, the palm of the hand represents about 1% of the skin surface.
Treatment of Psoriasis
Although there is no known cure for psoriasis, there are many available treatments; but not all treatments will work for each individual. The basis for treatment is to reduce inflammation and slow the skin cell division that is characteristic of the disease. The type of psoriasis, its severity and patient characteristics such as age, gender, overall health, lifestyle and medical history are all considered when determining a course of treatment. An effective therapy regimen requires experimentation to determine the proper course of therapy for the individual.
Many over-the-counter products may be used to soothe mild to moderate psoriatic lesions. These include: moisturisers - which soften skin and may lessen itching; salicylic acid - which may be used to remove scales; bath tar solutions, bath salts, bath oil and oatmeal - which may soften psoriatic skin and reduce itching; and aloe vera or jojoba - which are used to clear psoriatic lesions. These products may be effective for some patients and have few, if any, side effects.
Psoriasis is a difficult disease, both physically and emotionally. The course of the disease, as well as its response to treatment, varies for each individual.