Psoriasis - Basics Facts - What Is Psoriasis

Psoriasis is a common, chronic T cell mediated skin disorder that affects between 2-3% of the population [Gelfand JM, et al. Prevalence and treatment of psoriasis in the United Kingdom: a population-based study. Arch Dermatol. 2005 Dec;141(12):1537-41]. T cells are white blood cells that regulate the body's immune system. In psoriasis, T cells become overactivated, which triggers an inflammatory response that leads to the accelerated production of skin cells. Normally, the time between the production and shedding of skin cells is about 28 days, however, in psoriasis, the process accelerates to approximately 7 times faster, and results in poorly formed outer cells that do not shed properly. Instead, the accumulated dead skin cells pile up and produce the associated scaling. Although the exact cause is unknown, current evidence suggests that autoimmunity, along with genetic influences, are contributing factors.

Individuals with moderate-to-severe psoriasis may be significantly impacted not only by symptoms of the skin disorder, but also in terms of the affect on their quality of life. Frequently, joint involvement develops years later, and this associated disabling condition is known as psoriatic arthritis. Medical intervention under the supervision of a qualified physician is recommended for the management of psoriasis to slow or prevent disease progression and improve the quality of life of affected individuals.

Who Can Get Psoriasis?

Psoriasis can affect men and women in any age group. There is a genetic component to the psoriasis, but influence of inheritance is variable. Approximately 30% of people with this condition also have a first degree relative (that is parents, brothers, sisters and children) with psoriasis. The severity of psoriasis may vary amongst family members. For example, one member might have a very mild disease with only a couple of lesions, while another member may have more extensive involvement. A second type typically begins around age 60 and does not run in families.

Key Points

Psoriasis is chronic, non-contagious and reoccurring
Chronic plaque psoriasis is the most common and it affects about 90% of the psoriatic patient population
It produces red, scaly, well defined and/or thickened skin patches (also referred to as plaques) of varying sizes
Psoriasis can affect any part of your body, including the scalp, elbows, knees, lower back, and nails, but the face is usually not affected
It may include nail involvement and can eventually progress to the joints (arthritis)
Chronic lesions, particularly of the hands and feet, can produce persistent dryness, hyperkeratosis (thickening of the other layer of the skin), itching (pruritis), fissuring, and infection

Influencing Factors

The following is a list of potential triggering factors for psoriasis:

In approximately one-third of people with psoriasis, an injury to the skin (for example a scrape, scratch or bad sunburn) can induce psoriasis in the injured area - this is referred to as the "Koebner Phenomenon".
Stress
Alcohol
Smoking
Infections (e.g., streptococcal infections)
Certain drugs can trigger or worsen psoriasis (e.g., antimalarials, lithium, beta-blockers, antiotensin-converting, enzyme inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), iodine, digoxin and clonidine)

If you are on any of these medications, speak to your doctor to determine if it might be contributing to your condition. Do not stop taking any prescribed medication without consulting your physician, since it is not safe to discontinue them abruptly. If you have a sore throat and suspect a streptococcal infection, consult your physician to determine if antibiotic treatment is necessary.