Psoriasis

Psoriasis is a chronic (prolonged) inflammation of the skin, whose cause is unclear. Often there are red patches (plaques) on the skin covered by silvery scales of dead skin. The condition is not infectious and is not usually severe enough to affect general health.

Causes of psoriasis skin changes

In areas affected by psoriasis, there seems to be a rapid increase in the speed at which skin cells are replaced. Skin usually takes about 27 days to replace itself; in areas affected by psoriasis it may take only three or four days. New skin cells go rapidly to the surface before they are properly mature, forming the thick psoriatic patches. There is also a build up of white blood cells (called T-cells) under the skin, which causes inflammation.

It is thought that substances produced by the immune system may cause both the build up of white blood cells and the abnormal turnover of skin cells, but what makes the immune system behave in this way is unclear.

Who Gets Psoriasis

More than 4.5 million adults in the United States have been diagnosed with psoriasis, and approximately 150,000 new cases are diagnosed each year. An estimated 20% have moderate to severe psoriasis.

Psoriasis occurs about equally in males and females. Recent studies show that there may be an ethnic link. It seems that psoriasis is most common in Caucasians and slightly less common in African Americans. Worldwide, psoriasis is most common in Scandinavia and other parts of northern Europe. It appears to be far less common among Asians and is rare in Native Americans.

There also is a genetic component associated with psoriasis. Approximately one-third of people who develop psoriasis have at least one family member with the condition.

Research shows that the signs and symptoms of psoriasis usually appear between 15 and 35 years of age. About 75% develop psoriasis before age 40. However, it is possible to develop psoriasis at any age. After age 40, a peak onset period occurs between 50 and 60 years of age.

About 1 in 10 people develop psoriasis during childhood, and psoriasis can begin in infancy. The earlier the psoriasis appears, the more likely it is to be widespread and recurrent.

Psoriatic arthritis develops in roughly one million people across the United States, and 5% to 10% experience some disability. Psoriatic arthritis usually first appears between 30 and 50 years of age — often months to years after skin lesions first occur. However, not everyone who develops psoriatic arthritis has psoriasis. About 30% of people who get psoriatic arthritis never develop the skin condition.

Symptoms

Generally, the skin of the person suffering from the disease appears and irritated and may be covered with bright silvery scales. Sometimes there is also a little itching .The areas usually involved are the elbows, knees, the skin behind the ears, the trunk, and the scalp. The disease may also affect the underarms and genital areas. The lesions vary in size from minute papules to sheets covering large parts of the body. Quite often they are discs from half an inch to several inches in size. The lesions are always dry and rarely become infected.

Treatment

Currently, there is no cure for psoriasis. However, there are many treatment options that can clear psoriasis for a period of time. Each treatment has advantages and disadvantages, and what works for one patient may not be effective for another. Board-certified dermatologists have the medical training and experience needed to determine the most appropriate treatments for each patient.

Diagnosis

There are several forms of psoriasis, and each form has unique characteristics that allow dermatologists to visually identify psoriasis to determine what type, or types, of psoriasis is present. Sometimes a skin biopsy will be performed to confirm the diagnosis.

To choose the most appropriate treatment method, dermatologists consider several factors:

Type of psoriasis

Severity (the amount of skin affected)

Where psoriasis is located

Patient’s age and medical history

Effects psoriasis has on patient’s overall physical and emotional well-being

Types of Treatment

Psoriasis treatments fall into 3 categories:

Topical (applied to the skin) – Mild to moderate psoriasis

Phototherapy (light, usually ultraviolet, applied to the skin) – Moderate to severe psoriasis

Systemic (taken orally or by injection or infusion) – Moderate, severe or disabling psoriasis

While each of these therapies is effective, there are also drawbacks.

Some topicals are messy and may stain clothing and skin. Phototherapy can require 2 to 5 weekly visits to a dermatologist’s office or psoriasis clinic for several weeks. Many of the systemic medications have serious side effects and must be combined or rotated with other therapies to maximize effectiveness and minimize side effects. Research is being conducted to find therapies that provide safe, effective, easy-to-use treatment options that provide long-term relief.