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Psoriasis

How Is Psoriasis Treated?

Last modified: 
23/04/2012 - 16:46

Contributing Author: Guy Slowik FRCS

Unfortunately, none of the available treatments for psoriasis is a cure. Treatment can often control the disease for long periods, but the disease can come back when treatment stops. But new biological therapies in development should offer better control while reducing the number of side effects.

Treatment for psoriasis varies depending on:

  • the type of psoriasis
  • the extent and severity of the disease (how much of the skin is affected and how badly)
  • the age, sex, and lifestyle of the affected person
  • how the affected person has responded to treatment in the past.

In general, doctors treat psoriasis in three steps.

Step 1: Medications applied to the skin (topical therapy)

Step 2: Treatments that use light (phototherapy)

Step 3: Medications given as a pill or injection (systemic therapy)

These treatments can be combined in various ways to try to get the best outcome. Finding the most effective treatment for an affected individual can involve a lot of trial and error. What works for one person may not work for someone else. People with severe and extensive psoriasis may get the most relief and avoid or reduce side effects when treatments are rotated.

Treatments for psoriasis can often control the disease for long periods. However, none of the available treatments is a cure. The disease can come back when treatment stops.

Biologic agents are being introduced for the treatment of psoriasis and have substantial advantages over previously used systemic therapies because they have fewer risks and side effects. Two of the therapies currently being used, etanercept and remicade, are already available for the treatment of rheumatoid arthritis and Crohn's disease. Both therapies are tumor necrosis factor (TNF) blockers, which work by interfering with specific immune responses that are responsible for psoriasis. Alefacept was approved in Jan. 2003 and works by interfering with the t cell process.

Step 1: Medications applied to the skin (topical therapy)

Doctors usually use medications applied to the skin first to treat psoriasis. These medications are most useful for treating mild to moderate psoriasis. The medication that is best may depend on the type and location of the psoriasis. For example, ointments may be very effective for thick, flaky plaques on the body but messy and uncomfortable on the scalp.

Improvements have been made in how often these need to be applied. Once daily applications for corticosteroids, vitamin D(3) analogues and retinoids have been developed, and intermittent applications, a few times per week, are now possible for corticosteroids, which proved to be very effective with reduced side effects.

Topical steroids. Topical steroid medications are one of the most common treatments for mild to moderate psoriasis. They reduce redness (inflammation) and itching and stop the rapid build-up of dead skin cells. They come in varying strengths, from weak to highly potent and are available as creams, gels, lotions, ointments, or solutions. Generally stronger preparations are used on the scalp, knees, palms and feet while weaker creams or ointments are used on the face and other sensitive areas. A new foam for scalp psoriasis called clobetasol propionate has recently been approved. In foam form, it penetrates the skin easily - enhancing the effectiveness of the treatment.

Topical steroids can become less effective if used repeatedly for a long time. This is called resistance. The best outcome may be achieved when topical steroids are combined with other medications applied to the skin. However, steroid medication should not be stopped suddenly.

Steroids in the form of pills or injections are generally not used to treat psoriasis because they have too many serious side effects.

Long-term use of potent topical steroids on large areas of skin can produce side effects such as stretch marks, thinning and skin color changes, plus the appearance of small blood vessels through the skin. These medications should not be put on the face or on areas of the body where the skin folds, such as the armpits, groin, and between the toes.

Tar compounds. Crude coal tar is a byproduct of oil production. It makes the skin more sensitive to light. In its natural state it is a thick, brownish-black substance that is messy to apply to the skin. Refined coal tar preparations, many of which are available over the counter, may be more cosmetically acceptable.

Coal tar has been used for more than 100 years to treat psoriasis and it has few side effects. However, it does not work for everyone. In addition to being messy to use, it has a strong odor and can stain skin and clothing.

Coal tar can be combined with ultraviolet light treatment in the Goeckerman regimen for treating severe psoriasis. This regimen, developed at the Mayo Clinic, combines tar with gradually increasing exposure to ultraviolet light, which vary depending on the severity of the psoriasis and skin sensitivity. The regimen is usually performed daily in a supervised medical setting.

Anthralin. Anthralin is a synthetic medication that has an effect on enzymes in the skin cells of people with psoriasis. It comes in a variety of strengths and in the form of an ointment, cream, or paste. Generally it works best on people with plaque and guttate forms of psoriasis and it can be used with ultraviolet therapy. Side effects include irritation of normal skin.

In the past, old formulations of anthralin temporarily stained skin, clothing, and furniture purplish-brown. However, a new mixture of anthralin does not stain household items. It is applied to the skin at body-surface temperature. Warm water releases the active ingredient in this product, so it should be washed out with cold water.

In the so-called minutes therapy, anthralin cream is applied to skin plaques for 30 minutes to two hours, then thoroughly removed with a detergent-based soap and water. Over a period of weeks, redness and scales decrease and plaques gradually flatten. In the Ingram regimen, anthralin paste is applied to widespread plaques of psoriasis. This is followed by a tar bath and ultraviolet light treatment. This regimen produces significant clearing in about three weeks at a supervised day-treatment center.

Vitamin D. Synthetic vitamin D is also called calcipotriol or calcipotriene and is a chemical cousin of Vitamin D3. It is odorless and non-staining. It can be used alone but often works best in combination with other topical agents or phototherapy.

Applying the medication twice a day reduces scales by controlling the build-up of dead skin cells. Calcipotriene is most effective for mild to moderate psoriasis. It can irritate the skin and is not recommended for use on the face or genitals.

Calcipotriene's safety for the treatment of psoriasis that affects more than 20 percent of the skin is unknown. Using it on widespread areas of the skin may raise the amount of calcium in the body to unhealthy levels.

Vitamin D3 is not the same as the Vitamin D found in over-the-counter vitamin supplements. Vitamin D3 should not be taken by mouth because it may raise blood calcium levels and increase the risk of kidney stones. It should be used with caution in children.

Retinoids. These prescription medications are chemical cousins of Vitamin A and are used to treat a variety of skin conditions. Tazarotene is a synthetic retinoid introduced to treat mild to moderate plaque psoriasis, and psoriasis of the scalp and nails. Tazarotene clears skin more slowly than topical steroids but has fewer side effects. It may be used in combination with topical steroids or ultraviolet light treatment. Introduced in gel form, it is now available in a cream that may be better tolerated.

Tazarotene clears skin more slowly than topical steroids but has fewer side effects. It may be used in combination with topical steroids or ultraviolet light treatment.

Tazarotene can be irritating to normal skin and should be used with caution in skin folds. Like other retinoids, tazarotene can cause birth defects. Pregnant women must not use it. Women of childbearing age who use it must also use an effective method of birth control.

Non-prescription skin treatments. A variety of over-the-counter products may be helpful in treating psoriasis in some people. They will not work for everyone, but they are unlikely to cause harmful side effects.

  • Applied regularly over a long period, moisturizers can soothe the skin and relieve itching and scaling. Thick, greasy preparations that hold water in the skin usually work best.
  • Creams and lotions containing salicylic acid can help to remove scales. These products are sometimes used to boost the effectiveness of tar, anthralin, or topical steroids.
  • Soaking in bath water containing tar solutionsbath oiloiled oatmeal, and Epsom salts may remove scales and relieve itching.
  • Creams and lotions containing extracts of plants such as aloe vera and jojoba may be soothing to the skin.

Wrapping skin affected by psoriasis with cloth or tape after first applying a mild topical steroid is known as occlusion. This may improve or clear psoriasis in some people. Occlusion should be done with a doctor's guidance.

Step 2: Treatments that use light therapy (phototherapy)

Natural sunlight contains ultraviolet (UV) light. UV light kills T cells in skin, reducing redness and slowing the overproduction of skin cells that causes scaling.

Sunshine. Brief, regular periods of exposure to natural sunlight can improve or clear psoriasis in some people. This approach to treating psoriasis is called climatotherapy. Sunburn should be avoided because it can make psoriasis worse. Exposure to sunlight is not recommended for people who are sun-sensitive. Sun exposure can cause aging of the skin. An annual medical checkup is advised because sun exposure can increase the chance of skin cancer.

Ultraviolet therapy. Exposing the skin to UV light in carefully controlled doses is called phototherapy. Sunlight contains two kinds of UV light, known as UVA and UVB. Both can be used to treat psoriasis. In phototherapy, the affected person sits or lies inside a "light box," a booth fitted with special light-emitting tubes. Usually, people go to a doctor's office to receive phototherapy. Sometimes a light box can be purchased with a doctor's prescription for use at home.

  • UVB therapy. Treatment with UVB light is the safest form of phototherapy for widespread psoriasis or psoriasis that has not responded to medications applied to the skin. Usually three to five treatments a week are recommended, with a gradual increase in UV exposure depending on skin type. Significant clearing of psoriasis can be expected in one to three months.

    Exposure to UVB light must be carefully monitored to prevent sunburn. During treatment, the eyes must be shielded with goggles to guard against the possible formation of cataracts.

    Skin aging, wrinkling and eye damage may be a side effect of UVB treatment.

    UVB phototherapy may be combined with tar, anthralin, topical steroids, or other medications applied to the skin. The Goeckerman regimen, developed at the Mayo Clinic, uses crude coal tar, tar baths, and UVB treatment to treat widespread psoriasis. The Ingram regimen uses coal tar baths, anthralin paste, and UVB therapy.

  • PUVA. PUVA is used for widespread psoriasis or when other treatments have not been effective. It combines a medication called psoralen with careful exposure to UVA light. (PUVA stands for Psoralen plus UVA.) Psoralen may be taken by mouth or applied to the skin. It makes the skin more sensitive to light. Treatment is given two or three times a week, up to about 25 treatments. The amount of UV exposure may be gradually increased, depending on skin type. As with UVB therapy, significant clearing of psoriasis can be expected in one to three months.

    Compared with UVB therapy, PUVA clears skin more consistently with fewer treatments. However, PUVA has more short-term side effects, such as nausea, headache, fatigue, burning, and itching. When psoralen is taken by mouth, nausea may be avoided by taking food at the same time. As with UVB therapy, the eyes must be shielded with goggles during UVA exposure to guard against the formation of cataracts.

    Psoralen can be applied to the skin in the form of a cream, lotion, gel, or solution.

    • Paint PUVA. Psoralen is painted onto skin plaques such as those on the palms of the hands or soles of the feet.
    • Soak PUVA. The affected areas, such as the hands or feet, are immersed in a basin of water containing psoralen.
    • Bath PUVA. The body is immersed in a tub of water containing psoralen.

    After the paint, soak, or bath routine, the person is exposed to UVA light in a lightbox.

    UVA light is the same kind used in commercial tanning salons. Treating psoriasis in tanning salons is not recommended because attendants are untrained and the dose of UVA is not controlled. UVA therapy must be given in carefully controlled doses and supervised by a doctor.

    PUVA is recommended for people with moderate to severe psoriasis or who have not improved with other treatments. . Also, because Psoralen remains in the lens of the eye, patients must wear UVA blocking eyeglasses when exposed to sunlight from the time of exposure to psoralen until sunset that day. PUVA can be combined with some oral medications (retinoids and hydroxyurea) to increase its effectiveness. Simultaneous use of drugs that suppress the immune system, such as cyclosporine, have little beneficial effect and increase the risk of cancer.

    Long-term use of PUVA increases the risk of developing both squamous cell skin cancer and melanoma. Regular medical examinations are advised to check for signs of skin cancer.

    For more detailed information about melanoma, go to Melanoma.

Step 3: Medications given as a pill or injection (systemic therapy)

Doctors may prescribe medications that are given as a pill or an injection for severe psoriasis that does not respond to other treatments. Several new experimental biological therapies in development target specific steps in the pathogenesis of psoriasis. The first biological therapy was approved in January 2003. Initial data suggest improved safety over older agents such as methotrexate and ciclosporin, but more research is necessary.

  • Alefacept. In January 2003, the U.S. Food and Drug Administration approved Amevive (alefacept), the first biological therapy for psoriasis. The injected medication is used to treat adults with moderate to severe plaque psoriasis. Amevive treats plaque psoriasis through a unique immunosuppressive mechanism of action. Specifically, Amevive is believed to work by simultaneously blocking and reducing the cellular component of the immune system that is thought to play a significant role in the disease process.

    Patients taking this medication should have regular monitoring of white blood cell counts during therapy. Amevive must be administered under the supervision of a physician. The medication works by suppressing the immune system, which could potentially increase their chances of developing an infection or malignancy. Patients should inform their physician promptly if they develop any signs of an infection or malignancy while undergoing a course of treatment with Amevive. Because the effect of Amevive on pregnancy and fetal development, including immune system development, is not known, women who become pregnant while taking the medication are urged to register in the drug manufacturer’s registry.

  • Methotrexate. This medication slows down the build-up of dead skin cells by interfering with DNA and by suppressing the immune system and can have a dramatic effect on psoriasis. Methotrexate is also used to treat cancer. The doses used to treat psoriasis are much smaller than those used in cancer treatment. The drug is usually taken by mouth once a week, either in a single dose or in three doses taken 12 hours apart. A supplement of folic acid (a B vitamin) may be taken at the same time.

    Methotrexate is very effective for people with widespread psoriasis that does not respond to ultraviolet light treatment or to medications applied to the skin. It is also effective for psoriatic arthritis. Skin improvement usually begins within several weeks of starting treatment. Maximum improvement is usually seen within two to three months. Medications applied to the skin may be used to treat any remaining plaques.

    If psoriasis still does not clear completely, or if the drug dose must be lowered to reduce side effects, methotrexate may be combined with UVB or PUVA phototherapy or with another medication, such as a retinoid.

    People taking methotrexate must be closely monitored. The drug can cause liver damage. It can also decrease the body’s production of red and white blood cells and platelets. Chest x-rays, as well as regular blood tests, should be done to check the blood count and liver and kidney function. A periodic liver biopsy may also be recommended because the drug’s effects on the liver may not show up on blood tests. People who have liver disease or anemia should not take methotrexate.

    Methotrexate can cause birth defects. It cannot be used by pregnant women, women planning to become pregnant, or their male partners.

  • Retinoids. These drugs are related to Vitamin A. They normalize the growth of skin cells in psoriasis. Acitretin and isotretinoin are systemic vitamin A derivatives used in treatment of psoriasis. They are useful in treating severe forms of psoriasis, such as erythrodermic and pustular psoriasis that do not respond to other therapies.

    Retinoids cannot be used by pregnant women, women planning to become pregnant, or their male partners. Women who take acitretin must avoid pregnancy for up to three years after they stop taking the drug. Women also must not drink alcohol while they are taking acitretin and for two months after they stop taking it.

    Other possible side effects inclued dry skin, chapped lips, dryness of the eyes and nasal passages, hair thinning, sun sensitivity, and bone spurs of the long bones or spine. The drugs may also increase blood levels of both liver enzymes and triglycerides, a type of fat found in the blood. Reducing the dose of the drug usually reduces these side effects.

  • Cyclosporine. This drug is widely used to prevent the rejection of transplanted organs. It is used to treat severe, disabling psoriasis in people who cannot tolerate other therapies or for whom other therapies have not been effective.

    Cyclosporine works by suppressing the immune system in a way that slows the build-up of dead skin cells. Depending on the daily dose, the drug can clear most or all skin plaques within several weeks to a month. However, when a person stops taking the drug, the disease can come back.

    People taking cyclosporine must be closely monitored by a doctor. The drug can cause high blood pressure and damage kidney function. It is not recommended for people who have a weak immune system or by people who have used ultraviolet light treatment a lot. Women who are pregnant, planning to become pregnant, or breast-feeding also must not use it.

    Cyclosporine may also be used as a short-term crisis therapy. Other therapies with different side effects are then used to maintain the clearing of skin plaques.

  • Hydroxyurea. This drug reduces the build-up of dead skin cells by interfering with DNA. Like methotrexate, hydroxyurea is also used to treat cancer. In psoriasis, it may have fewer side effects than methotrexate or cyclosporine but it is also less effective. It is sometimes used in combination with ultraviolet light treatment.

    Possible side effects of hydroxyurea include anemia and a decrease in white blood cells and platelets. Like methotrexate and cyclosporine, it must not be used by women who are pregnant or planning to become pregnant.

Rotating Treatments

All of the treatments used for widespread, severe psoriasis have side effects when used for a long time. One way to reduce side effects is to use one treatment (or combination of treatments) for one to two years, then switch to another treatment, and continue in this fashion through a series of different treatments. This is called rotational therapy.

If the skin clears up, treatment is stopped until psoriasis reappears. Then the cycle of rotating treatments begins again.

This article continues: 

Psoriasis

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From Andrew Maynard - Chair of the University of Michigan Department of Environmental Health Sciences, with help from David Faulkner - 2013 Master of Public Health graduate.