Psoriasis

Medical Dermatology

Skin Conditions

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Psoriasis is a persistent skin disorder in which there are red, thickened areas with silvery scales, most often on the scalp, elbows, knees, and lower back. Some cases, of psoriasis are so mild that people don¹t know they have it. Severe psoriasis may cover large areas of the body. Dermatologists can help even the most severe cases.

Psoriasis is not contagious and cannot be passed from one person to another, but it may occur in members of the same family. In the United States, two out of every hundred people have psoriasis (four to five million people). There are approximately 150,000 new cases that occur each year.

The cause is unknown. However, recent discoveries point to an abnormality in the functioning of cells which trigger inflammation and the immune response in the skin. Because of the inflammation, the skin grows too rapidly. Normally, the skin replaces itself in about 30 days, but in psoriasis, the process speeds up and replaces itself in three to four days. This results in thickened red skin and thick white scale.

People often notice new breakouts 10 to 14 days after the skin is cut, scratched, rubbed, or severely sunburned. Psoriasis can also be activated by infections, such as strep throat, and by certain medicines (beta blockers, lithium, etc.) Flare-ups sometimes occur in the winter, as a result of dry skin and lack of sunlight.

Psoriasis comes in many forms. Each differs in severity, duration, location, shape, and pattern of the scales. The most common form, called plaque psoriasis, begins with little red bumps. Gradually, these become larger, and scales form. While the top scales flake off easily and often, scales below the surface stick together. These small red areas can enlarge. Scalp, elbows, knees, legs, arms, genitals, nails, palms, and soles are the areas most commonly affected by psoriasis. It will often appear in the same place on both sides of the body. Nails with psoriasis frequently have tiny pits in them. Nails may loosen, thicken, or crumble, and are difficult to treat. Inverse psoriasis occurs in the armpit, under the breasts, and in skin folds around the groin, buttocks, and genitals. This form is usually flat and red and without scale. Guttate psoriasis usually affects children and young adults. It often starts after an illness like strep. Many small, red, scaly spots appear on the skin and it often clears up by itself in weeks or a few months. Up to 30% of people with psoriasis may have symptoms of arthritis and 5-10% may have some functional disability from arthritis of various joints. In some people, the arthritis is worse when the skin is very involved. Sometimes the arthritis improves as the skin improves.

Treatment is based on a patient¹s health, age, lifestyle, and the severity of the psoriasis. Different types of treatments and several visits to your dermatologist may be needed. The goal is to reduce inflammation and to control shedding of the skin. Moisturizing creams and lotions loosen scales and help control itching.

Your dermatologist may prescribe medications to apply on the skin containing cortisone, synthetic vitamin D, vitamin A derivatives, tar, or anthralin. These may be used in combination with natural sunlight or ultraviolet light. The more severe forms of psoriasis may require oral or injectable medications with or without light treatment.

Sunlight exposure helps the majority of people with psoriasis but it must be used cautiously. Various ultraviolet light therapies may be given in a dermatologist's office.

New therapies have been gaining popularity and may be indicated if the psoriasis is severe enough and has not responded to first line treatments. These drugs are called the biologics and are designed to interrupt the inflammatory pathway that leads to the disease. These include Alefacept, Etanercept, Infliximab, Adalimumab and Efalizumab.