Priya K. Young, MD, Assistant Professor of Dermatology at the Medical College of Wisconsin. Dr. Young treats patients aged 17 or older at the Froedtert & Medical College Dermatology Clinic.
Psoriasis causes patches of thick, red skin with silvery scales. These patches can itch or feel sore. They are often found on the elbows, knees, other parts of the legs, scalp, lower back, face, palms, and soles of the feet, but they can even show up in places like fingernails, toenails, genitals, and inside the mouth.
People often have the mistaken impression that they can catch psoriasis from someone who has it. "It's important for people to know that psoriasis is not contagious. It is a chronic inflammatory disease and cannot be caught by coming into contact with someone who suffers from it," Dr. Young says.
Causes
"Anyone can have psoriasis, from infants to older people. Some people have a genetic predisposition to the disease," Dr. Young says. About one-third of those who experience the condition have inherited the illness from a family member, according to studies.
"There is a particular type of inflammatory cell that accumulates in the skin. Some people have mild disease and some have a severe form of it," she explains.
Psoriasis begins in the immune system, mainly with a type of white blood cell called a T-cell. T-cells help protect the body against infection and disease. With psoriasis, T-cells are put into action by mistake and become so active that they set off other immune responses, which lead to swelling and fast turnover of skin cells.
There are certain triggers that can cause psoriasis to get worse, including infections, stress, changes in the weather, and certain medicines. These triggers vary from person to person and individuals might be able to learn to avoid certain triggers.
Diagnosis
Diagnosing psoriasis is straightforward if the doctor examines the skin and sees the characteristic patches that are typical of the disease. "We usually are able to look at the skin and make a determination, however sometimes a biopsy is necessary," Dr. Young says.
Unfortunately, there is no permanent cure for psoriasis right now, but there is relief. A variety of treatment options are available. "Treatment depends on the severity of the disease. There is more than one type of psoriasis," Dr. Young says. Common types of psoriasis include:
- Plaque psoriasis. This is the most common type of psoriasis, named for the patches that appear on the skin. It can occur on any part of the body.
- Guttate psoriasis. This type most often affects children and looks almost like droplets on the skin.
- Other types of psoriasis appear on specific parts of the body, such as seborrheic psoriasis, which affects the scalp and may resemble dandruff.
In addition, there is a type of arthritis that can sometimes be associated with psoriasis. "Psoriatic arthritis affects about ten percent of those who have psoriasis. It causes degenerative joint pain and usually affects people in later years," Dr. Young explains.
Treatments
Fortunately, there are choices when it comes to treatment of psoriasis. When deciding how to treat individual cases of psoriasis, physicians will consider the type of psoriasis, the seriousness of the patient's disease, the size of the psoriasis patches, and how the patient reacts to various treatments.
All treatments do not work the same for everyone, but doctors will try different combinations until they find the best solution for each patient. The primary types of treatment are topical, oral, and light therapy.
Topical treatments are applied directly to the skin. They range from over-the-counter medications to more powerful prescription steroids. "Mild disease can be treated with topical preparations containing steroids, vitamin D, or topical retinoids. They can help reduce swelling and clear lesions," Dr. Young says.
Light therapy also can be effective against psoriasis. "Light boxes are used that expose the skin to measured doses of ultraviolet light within a specific UV range," Dr. Young says. Light is used to treat moderate or severe psoriasis that is resistant to topical preparations. One treatment called PUVA uses a combination of a drug that makes skin more sensitive to light and ultraviolet A light.
Systemic treatments, including oral medications such as oral retinoids, are also available to treat the more severe forms of psoriasis. Unfortunately, some of these drugs have serious side effects.
In recent years, drugs known as biologic response modifiers (BRMs) have been developed to treat severe psoriasis. This is a new class of drugs that work in the immune system. "Injectable biologic agents are relatively new treatments that have come along within the last five years," Dr. Young says.
Some of these medications are just beginning to be approved for the treatment of psoriasis, but they show potential.
"There is a lot going on in psoriasis research. An entire field is devoted to it and it is showing promise," Dr. Young notes.
JoAnn Petaschnick
HealthLink Contributing Writer
