Psoriasis & Psoriatic Arthritis
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Psoriasis is a persistent, inflammatory skin condition. Psoriasis is not contagious, so it cannot be passed from one person to another. Psoriasis does, however, have a tendency to run in families, meaning it can be an inherited condition.
WHAT CAUSES PSORIASIS?
While the cause is unknown, it is believed that the person's immune system mistakenly activates T cells, a type of white blood cell. Once activated, the T cells trigger inflammation, which causes the skin to grow too rapidly. Normally, the skin replaces itself about every 30 days. When the process speeds up and the skin replaces itself in three to four days, psoriasis develops.
A "trigger" is usually needed to make psoriasis appear, whether for the first time or the twentieth. Psoriasis can be triggered by stress; an infection, such as strep throat; and by taking certain medicines, such as interferon and lithium. Cold, dry winter weather and lack of sunlight also can trigger psoriasis. Others see psoriasis flare 10 to 14 days after their skin is injured, such as by a cut, scratch, or severe sunburn. This is known as Koebner's phenomenon.
Psoriasis on the elbow
TYPES OF PSORIASIS
There are five major types of psoriasis, each with unique signs and symptoms:
- Plaque psoriasis
- The most common type, plaque psoriasis appears as patches of raised, reddish skin covered by silvery-white scale. Patches frequently form on the elbows, knees, lower back, and scalp, but can occur anywhere on the skin.
- Guttate psoriasis
- Appearing as small, red spots, guttate psoriasis usually affects children and young adults. It often starts after a sore throat, and frequently clears up by itself in weeks or a few months.
- Pustular psoriasis
- Characterized by white pustules surrounded by red skin, pustular psoriasis tends to confine itself to certain areas of the body, usually the palms and soles. Dermatologists call this "localized pustular psoriasis." When widespread, the condition is known as "generalized pustular psoriasis," which is a rare and severe form of psoriasis that can be life threatening.
- Inverse psoriasis
- This type occurs when smooth, red lesions form in the skin folds. Lesions can appear in the armpit, under the breasts, and around the groin, buttocks, and genitals.
- Erythrodermic psoriasis
- Causing widespread redness with severe itching and pain, erythrodermic psoriasis can be life threatening.
Psoriasis affecting nails
When psoriasis occurs on the scalp, psoriasis often causes silvery-white scale, which may be misdiagnosed as dandruff. Psoriatic nails frequently have tiny pits. The nails may loosen, thicken, or crumble. These signs may be misdiagnosed as a nail infection. Both scalp psoriasis and nail psoriasis can be difficult to treat.
PSORIATIC ARTHRITIS
Between 10% and 30% of people who develop psoriasis get a related form of arthritis called "psoriatic arthritis," which causes inflammation of the joints. Psoriatic arthritis is a lifelong condition that causes deterioration, pain, and stiffness in the joints. Medication can help prevent joint deformities and disability if used early. Without treatment, permanent joint degeneration and destruction can occur.
HOW IS PSORIASIS TREATED?
While psoriasis cannot be cured, a number of treatment options can help control psoriasis.
A patient's health, age, lifestyle, and the severity of the psoriasis determine which treatment options are appropriate.
TYPES OF TREATMENT
TOPICALS
- Corticosteroids (cortisone)
- Cortisone is a medication that reduces inflammation and may clear the skin temporarily and control psoriasis in many patients. Preparations can be made weak or strong depending on where it is used on the body, and dressings may be applied to enhance the effectiveness of the medication. Corticosteroids must be used cautiously as side effects of stronger preparations include thinning of the skin, dilated blood vessels, bruising, stretch marks, and skin color changes. Stopping these medications suddenly may result in a flare-up.
- When used for many months, psoriasis can become resistant to the corticosteroid. Difficult-to-treat spots may be treated with an injection of a corticosteroid.
- Anthralin
- Often effective on tough-to-treat thick patches of psoriasis, anthralin decreases the skin's rapid growth rate and reduces inflammation. Newer preparations and treatment methods minimize the traditional side effects of skin irritation and staining.
- Calcipotriene
- Useful for individuals with localized psoriasis, calcipotriene may be combined with other treatments. Apply as instructed to avoid side effects, such as skin irritation.
- Retinoids
- This medication may be used alone or in combination with topical corticosteroids for treatment of localized psoriasis. Women who are, or may become, pregnant should not use topical retinoids.
- Coal Tar
- For more than 100 years, coal tar has been used safely and effectively to treat psoriasis. Today's products are greatly improved and less messy. Stronger prescriptions can be made specifically to treat difficult areas.
Light Therapy
Ultraviolet (UV) light, which is found in sunlight, slows the rapid growth of skin cells. Patients with psoriasis may receive light therapy treatments at a dermatologist's office, psoriasis center, or hospital. Psoriasis patients who live in warm climates may be directed to carefully sunbathe. Under a dermatologist's care, light therapy offers many patients a safe and effective treatment option. Seek the advice of your dermatologist before self-treating with natural or artificial sunlight.
PUVA
PUVA stands for "psoralen + UVA," which are the two components of this treatment. Used to treat widespread psoriasis and psoriasis that has not responded to other therapies, PUVA is effective in approximately 85% of cases. To receive PUVA, a patient is given a drug called psoralen, which may be taken orally or applied to the psoriasis. The patient is then exposed to a carefully measured amount of a special form of ultraviolet (UVA) light. Clearing usually occurs after approximately 25 PUVA treatments, which are given over a two- or three-month period. Keeping psoriasis under control requires about 30 to 40 treatments a year. PUVA treatments over a long period increase the risk of premature aging, freckling, and skin cancer. Dermatologists and their staff monitor PUVA treatment very carefully.
Goeckerman Treatment
Named after the Mayo Clinic dermatologist who first reported it, this treatment combines coal tar dressings with UV light. Used to treat patients with severe psoriasis, Goeckerman treatment is performed daily for a prescribed amount of time. Access to this therapy is limited because only a few specialized centers in the United States offer it.
SYSTEMIC THERAPIES
- Methotrexate
- This anti-cancer medication can dramatically clear psoriasis. Because methotrexate can cause serious side effects, particularly liver disease, it is reserved for treating moderate to severe psoriasis that has not responded to other therapies. As methotrexate can cause birth defects, it should not be used by pregnant women, nor by men or women who are trying to conceive a child. Conception should be avoided for at least 3 years after stopping methotrexate.
Patients taking an oral retinoid (methotrexate) require close monitoring, which includes regular blood tests. - Cyclosporine
- This medication suppresses the immune system and is used to prevent rejection of a transplanted organ. It is generally reserved for patients with severe psoriasis who have not responded to other therapies. Due to potential side effects, patients taking cyclosporine require close medical monitoring, which includes regular blood tests.
BIOLOGIC AGENTS
Given by injection or infusion, biologics also are systemic medications that pinpoint precise immune responses involved with psoriasis. The biologics used to treat psoriasis are: alefacept, etanercept, efalizumab, infliximab and adalimumab.
To learn more about psoriasis, call toll free (888) 462-DERM (3376) to find a dermatologist in your area or go to www.skincarephysicians.com/psoriasisnet.
Supported through an educational grant from:
AAD Web site: www.aad.org
1-888-462-DERM
Images used with permission of the American Academy of Dermatology
National Library of Dermatologic Teaching Slides
© 2007 American Academy of Dermatology
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