What is psoriasis?
Psoriasis is a persistent skin disease that got its name from the Greek word for “itch.” The skin becomes inflamed, producing red, thickened areas with silvery scales, most often on the scalp, elbows, knees, and lower back. In some cases, psoriasis is so mild that people don’t know they have it. At the opposite extreme, severe psoriasis may cover large areas of the body. Psoriasis cannot be passed from one person to another, though it is more likely to occur in people whose family members have it.
Psoriasis comes in many forms. The most common form begins with little red bumps. Gradually these grow larger and scales form. While the top scales flake off easily and often, scales below the surface stick together. When they are removed, the tender, exposed skin bleeds. These small red areas then grow, sometimes becoming quite large.
Elbows, knees, groin and genitals, arms, legs, scalp, and nails 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 have tiny pits on them. Nails may loosen, thicken or crumble and are difficult to treat. Inverse psoriasis occurs in the armpit, under the breast and in skin folds around the groin, buttocks, and genitals. Guttate psoriasis usually affects children and young adults. It often shows up after a sore throat, with many small, red, drop-like, scaly spots appearing on the skin. It often clears up by itself in weeks or a few months.
About seven percent of psoriasis patients also have arthritis, which fortunately is not too severe in most people. In some people, the arthritis is worst when the skin is very involved. Sometimes the arthritis improves when the condition of the patient’s skin improves.
What causes psoriasis?
The cause is unknown. However, recent discoveries point to an abnormality in the functioning of key white cells in the blood stream triggering inflammation in the skin. This causes the skin to shed itself too rapidly, every three to four days.
People often notice new spots 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. Flare-ups sometimes occur in the winter as a result of dry skin and lack of sunlight.
How is psoriasis treated?
The goal is to reduce inflammation and to slow down rapid skin cell division. Moisturizing creams and lotions loosen scales and help control itching. Special diets have not been successful in treating psoriasis.
Cortisone creams, ointments, and lotions may clear the skin temporarily and control the condition in many patients. Weaker preparations should be used on more sensitive areas of the body such as the genitals, groin, and face. Stronger preparations will usually be needed to control lesions on the scalp, elbow, knees, palms and soles, and parts of the torso and may need to be applied under dressings. These must be used cautiously and with the dermatologist’s instruction. Side effects of the stronger cortisone preparations include thinning of the skin, dilated blood vessels, bruising, and skin color changes. Stopping these medications suddenly may result in a flare-up of the disease. After many months of treatment, the psoriasis may become resistant to the steroid preparations.
The dermatologist may inject cortisone in difficult-to-treat spots. These injections must be used in very small amounts to avoid side effects.
A variety of non-prescription and prescription shampoos, oils, solutions, and sprays are available. Most contain coal tar or cortisone. The patient must take care to avoid harsh shampooing and scratching the scalp.
A medication that works well on tough-to-treat thick patches of psoriasis is Anthralin. It can cause irritation and temporary staining of the skin and clothes. Newer preparations and methods of treatment have lessened these side effects.
A synthetic Vitamin D, calcipotriene, is now available in prescription form. It is useful for individuals with localized psoriasis and can be used with other treatments. Limited amounts should be used to avoid side effects. Ordinary Vitamin D, as one would buy in a drug store or health food store, is of no value in treating psoriasis.
For more than l00 years, coal tar has been used to treat psoriasis. Today’s products are greatly improved and less messy. Stronger prescriptions can be made to treat difficult areas.
The Goeckerman Treatment is named after the Mayo Clinic dermatologist who first reported it in 1925. Combining coal tar dressings and ultraviolet light, it is used for patients with severe psoriasis. The treatment is performed daily in specialized centers. Ultraviolet exposure times vary with the kind of psoriasis and the sensitivity of the patient’s skin.
Sunlight and ultraviolet light slow the rapid growth of skin cells. Though ultraviolet light or sunlight can cause skin wrinkling, eye damage, and skin cancer, light treatment is safe and effective under a doctor’s care. People with psoriasis all over their bodies may require treatment in a medically approved center equipped with light boxes for full body exposure. Psoriasis patients who live in warm climates may be directed to carefully sunbathe. Seek the advice of a dermatologist before self-treating with natural or artificial sunlight.
Narrow Band UVB (NBUVB)
When psoriasis has not responded to other treatments or is widespread, NBUVB is effective in 80-90 percent of cases. The treatment name comes from exposure to a carefully measured amount of a special form of ultraviolet (Narrow Band UVB) light. It takes approximately 15-20 treatments, over a two- or three-month period, before clearing occurs. About 15-20 treatments a year are usually required to keep the psoriasis under control.
Methotrexate is an oral anti-cancer drug that can produce dramatic clearing of psoriasis when other treatments have failed. Because it can produce side effects, particularly liver disease, regular blood tests are performed. Chest x-rays and occasional liver biopsies may be required. Other side effects include upset stomach, nausea and dizziness.
Prescription Vitamin A-related drugs may be prescribed alone or in combination with ultraviolet light for severe cases of psoriasis. Side effects include dryness of the skin, lips and eyes, elevation of fat levels in the blood, and formation of tiny bone spurs. Retinoids should not be used by women of child-bearing age, as birth defects may result. Close monitoring by a dermatologist is required together with regular blood tests.