Prognosis

Although psoriasis is not fatal, it can increase the risk for drug and alcohol abuse that, in some studies, has increased mortality rates in psoriasis patients. Even in its mildest form, psoriasis can still cause itching, burning, stinging, and bleeding. These symptoms can be very debilitating in more severe cases.

Severity of psoriasis itself ranges from one or two flaky inflamed patches to widespread pustular psoriasis that, in rare cases, can be life threatening. To help determine the best treatment for a patient, doctors usually classify the disease as mild to severe. The classification depends on how much of the skin is affected:

• Mild psoriasis affects less than 3% of the body surface. Most cases of psoriasis are limited to less than 2% of the skin.
• Moderate psoriasis covers 3 - 10% of the skin.
• If more than 10% of the body is affected, the disease is considered severe.

The palm of the hand equals 1% of the body. It is important to remember, however, that the severity of the disease is also measured by its effect on a person’s quality of life.

Some forms of psoriasis can be very resistant to treatment even though they are not categorized as severe. They include:

• Any psoriasis on the palms and soles
• Inverse psoriasis (which occurs in the folds of the skin)
• Scalp psoriasis
• Psoriatic arthritis

Course of Psoriasis

Psoriasis is lifelong and not curable. Although it is also marked by rapid cell growth, psoriasis is neither cancerous nor contagious. In general, studies report the following features of its course:

• The condition almost always relapses. In a few cases, large areas of plaque can persist for years.
• Psoriasis nearly always goes into remission, however, often clearing on its own. In one study, 30% of patients reported untreated psoriasis going into remissions that lasted 1 - 54 years.
• Psoriasis can improve during pregnancy, especially during the second and third months. Increased levels of estrogen may be responsible for this improvement. Relapse may occur after giving birth.

Emotional and Social Consequences

Effect on Quality of Life. The emotional and social consequences of psoriasis should not be underestimated.

• Many patients suffer severe humiliation and depression if plaques are visible. Some even withdraw from society and become isolated.
• Some patients are forced to leave their jobs and go on disability if the condition becomes incapacitating.

Researchers have reported the following:

• Surveys of patients with psoriasis report a negative mental and physical impact that is nearly equivalent to that of other major chronic conditions, including cancer, high blood pressure, diabetes, heart disease, and depression.
• In one study, 75% of patients reported that psoriasis hurt their confidence
• Another study reported that 8% of people with psoriasis felt their life was not worth living.

Higher Risk for Substance Abuse. Some patients, particularly men, use alcohol and smoking as self-medication to reduce the emotional consequences of psoriasis. In fact, studies have found that people with psoriasis have higher mortality rates, mostly from heavy drinking. Smoking has also been cited as a major risk, particularly for pustular psoriasis. Some experts believe that drinking and smoking may actually cause biological damage that contributes to psoriasis itself.

Physical and Medical Complications of Psoriasis

Folate Deficiency in Severe Psoriasis. Severe psoriasis can also cause folate deficiency. Folate is a B vitamin that is important for nerve function, preventing birth defects. It also prevents elevations of homocysteine, a factor that may play a critical role in heart disease.

Skin Cancers. In one study, patients with severe psoriasis (who receive medications that affect the whole body) were at higher than normal risk for developing cancers, primarily skin cancers and lymphomas. The risk was not any higher for patients with milder psoriasis. There is some indication, however, that patients with psoriasis have a higher risk for non-melanoma skin cancers regardless of treatments.

Complications of Erythrodermic and Pustular Psoriasis

Impaired Temperature Regulation. Erythrodermic psoriasis, in which psoriasis covers the entire skin, can cause abnormalities in the body's ability to regulate temperature.

Zumbusch Psoriasis. A combination of erythrodermic and pustular psoriasis causes a serious condition called Zumbusch psoriasis:

• The condition can develop abruptly.
• Symptoms may include fever, chills, weight loss, and muscle weakness.
• Patients may develop excessive fluid build-up, protein loss, and electrolyte imbalances. In such cases, hospitalization is required. Fluid and chemical balances must be restored and temperature stabilized as soon as possible.

Zumbusch psoriasis can be life threatening, particularly in the elderly. The condition is very rare in children and, if it occurs, tends to improve more quickly than in adults, possibly even without medication.

Complications of Psoriatic Arthritis

Most cases of psoriatic arthritis (PsA) are mild, but complications can occur:

• Severe joint deformity and destruction (called arthritis mutilans) may develop, generally in the small joints of the hands and feet. Studies report this happens in about 5 - 16% of patients. Psoriasis patients with other arthritic conditions (osteoarthritis or rheumatoid arthritis) in the joints of the fingers tend to have a higher risk.
• People with PsA may have a higher risk for respiratory illnesses.

Some earlier studies indicated that patients with psoriatic arthritis had a shorter lifespan than the general population, but more recent studies found no significant difference.