Psoriasis Causes & Treatments

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Psoriasis is an unsightly skin disorder that affects over 5 million Americans. It results from skin cells malfunctioning so that they reproduce much faster than is normal, leaving thickened, raised patches of red, scaly skin. Psoriasis comes in several forms and can range from mild to severe and disabling. Sadly, there is still no cure for psoriasis, but don't be discouraged: There are many different treatments, both topical and systemic, that can clear it for periods of time. Experimenting with a variety of options is essential, but all require a doctor’s attention and, most importantly, patient compliance.
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What is Psoriasis?

Psoriasis is a chronic recurring skin disorder, identified by the presence of thickened scaly areas and papules (small, solid, often-inflamed bumps that, unlike pimples, do not contain pus or sebum). These bumps are usually slightly elevated above the skin surface, sharply distinguishable from normal skin, and often red to reddish brown in color. They are usually covered with small whitish or silver scales that stick to the cyst-like swelling and, if scraped off, may bleed or ooze. For some, psoriasis may be nothing more than a few small, scaly patches at the hairline or on the sides of the nose, for others the disease can cover the entire body. Most typically, the elbows, knees, scalp, and chest are afflicted. Despite how many people struggle with psoriasis, fewer than 2 million people seek medical treatment for it.

No one knows for certain exactly what causes psoriasis and there is no cure, although the latest studies strongly suggest it may be related to an immune system problem that triggers inflammation. Research has shown that psoriasis is triggered by the activation of T-cells (a type of white blood cell). These cells affect the immune system and release cytokines (chemical messengers that stimulate the production of other substances, both positive and negative). In people with psoriasis, these cytokines send faulty messages causing skin cells to reproduce and mature at an enhanced rate. This miscommunication leads to the visible lesions and scaling in psoriasis. A normal skin cell matures in 28 to 45 days, while a psoriatic skin cell matures in only 3 to 6 days.

Recent studies are now leading researches to believe misbehaving cytokines can also increase insulin resistance in the liver and muscles, and destroy insulin-producing cells in pancreas, leading to the development of diabetes. In fact, there is now evidence that people diagnosed with severe psoriasis are nearly twice as likely to develop diabetes, and those with mild psoriasis are more than 1.5 times as likely. This news is particularly troubling, as diabetes can carry with it a whole separate set of skin concerns, including an increased risk of bacterial folliculitis and fungal infections like ringworm.

Both men and women can get psoriasis at any age, but most often it strikes persons in their 20s and 30s. Still, it isn't unusual to start noticing red, swollen, flaky bumps on your skin late in life. It is also believed that psoriasis is genetic: one third of patients have family members who also suffer from this unsightly skin condition.

Of the various therapies available to treat psoriasis, it is generally best to start with those that have the least-serious side effects, such as topical steroids (cortisone creams); topical vitamin D preparations, retinoids, salicylic acid, coal-tar creams, lotions, cleansers, or shampoos; prescription topical medicines, and careful exposure to sunshine. If those methods are not successful, you can proceed to the more serious treatments involving oral medications. More often than not, successful treatment requires a combination of methods.

Topical Treatments

Phototherapy/Sunlight: This may sound contradictory to our usual warnings about avoiding prolonged, unprotected sun exposure, but extended periods of time in the sun (also referred to as "climatotherapy") can significantly improve, or even clear, psoriasis. In fact some research indicates that 60% of those using this kind of treatment can obtain relief for a period of time. Ultraviolet (UV) light from the sun suppresses the skin’s immune response and, therefore, reduces that type of inflammation, resulting in a slowed overproduction of skin cells that cause scaling. Daily, short, nonburning exposure to sunlight clears or improves psoriasis in many people. Therefore, sunlight may be included among initial treatments for the disorder. Of course, this convenient, inexpensive treatment has serious drawbacks including advanced skin aging, far greater risk of skin cancer, and impaired immune response that can cause other health problems. Given the wide range of options for treating psoriasis that do not involve sun exposure, it is not recommended as often it once was.

UVB lamps: When real sunlight isn't available, an alternative to natural sunlight exposure is medically supervised administration of narrow-band ultraviolet B (UVB) lamps. UVB light is also used when topical treatments have failed, or in combination with topical treatments. The short-term risks of using controlled narrow-band UVB exposure to treat psoriasis is minimal, and long-term studies of large numbers of patients treated with narrow-band UVB have not demonstrated an increased risk of skin cancer, suggesting that this treatment may be far safer than sunlight. It is understood that narrow-band UVB lamps are safer because they do not emit UVA light and control the range of UVB impact. Sunlight has both ultraviolet A (UVA) and UVB radiation and it is believed that UVA is far more dangerous than UVB. A great deal of research points to UVA as the main cause for skin cancer and skin aging. Narrow-band UVB treatments are considered one of the most efficacious and cost-effective therapies for moderate to severe psoriasis, with the least amount of risk. This type of therapy is generally effective for 2/3 of psoriasis patients (Source:

It is important to point out that tanning beds or sun beds found in salons or spas are mostly fitted with UVA bulbs that emit minimal UVB emissions. Unfortunately, these are widely used by those with psoriasis but they're minimally effective.

UVB emitting lasers: A relatively new treatment for psoriasis is the use of lasers that emit narrow-band UVB light. It can clear skin lesions faster than direct sunlight or UVB lamps, and 70% of those receiving this treatment can be almost completely free of lesions after 10 treatments.

These lasers work in a manner similar to controlled UVB phototherapy (described above), in that a specific wavelength of light is directed toward the lesions. The light is believed to initiate the death of T-cells, rendering them unable to trigger the immune system to signal rapid cell proliferation. The most well-known laser for psoriasis is the 308nm (nanometer) excimer laser. It emits a single wavelength, and unlike UVB treatment, the excimer laser can be focused solely on psoriatic lesions, thus sparing the surrounding healthy skin from radiation. As a result, this laser can be used at a strength that is six times more potent than UVB radiation. The result? Better clearance of psoriasis lesions with fewer treatments, typically 4-10 sessions compared to 25-30 for UVB treatments.

Lasers: Other types of lasers such as ablative (meaning injurious) options such as the CO2 and Erbium: YAG lasers have been used to treat psoriasis, but the results have been mixed. Pulsed dye lasers have had a successful treatment history, with 585nm being the most common wavelength used. The light emitted by this device targets the blood vessels contributing to the formation of lesions. Extended clearance of lesions is a common outcome for many psoriasis patients undergoing PDL treatments, though not all lesions respond the same. For example, you may get great results on your arm or elbow, but see minimal change in facial lesions. This inconsistency is attributed to the underlying (dermal) blood pattern affecting each lesion. In general, larger and redder lesions respond less favorably than lighter ones. Despite this news, the excimer laser is still deemed the best choice for successful treatment of psoriasis lesions.

Coal tar: Treating psoriasis with coal tar is a very old option that isn't used as frequently as it once was. It is a topical medication available both over the counter and by prescription; the difference is in the potency and amount of coal tar the medication contains, which ranges from 1% to 5% in creams and ointments. Coal tar inhibits the substances in skin that incite rapid cell proliferation, thus reducing the appearance and severity of psoriasis. Coal tar can be combined with other psoriasis medications (like topical steroids) or with sunshine (UV light). However, coal tar can make the skin more sensitive to UV light, and extreme caution is advised when you combine coal tar use with UV therapy (or exposure to the sun) to avoid getting a severe burn or causing skin damage. Other downsides to coal tar are the irritation it can cause, the smell, and its tendency to stain clothes (Source: These aspects are what prevent many with psoriasis from adhering to a regimen of coal tar treatments.

Anthralin or dithranol: Similar to coal tar, anthralin (also called dithranol) is a topical prescription medication that has been used to treat psoriasis for decades. It works best in cases of mild to moderate psoriasis. Although anthralin's action on skin is not clear, it appears to inhibit cell proliferation and can be very effective in treating psoriasis. It is often used in combination with other treatments. It has few serious side effects but can cause extreme irritation or burn the normal-appearing skin surrounding psoriatic lesions. Anthralin also stains anything it comes into contact with. It is prescribed in a range of concentrations, but the most effective form is a hard paste that is very difficult to apply, requiring a great deal of patience; also, it can't be used over inflamed lesions, and must not get on the face. There are a variety of regimens for its use, but the negative side effects and cumbersome, time-consuming application process really limit its appeal.

Vitamin D Analogues: A range of studies have demonstrated an impressive improvement in psoriatic lesions with the topical application of calcipotriene (trade name Dovonex), a derivative of vitamin D3, when used alone or in combination with other therapies. By the way, this calcipotriene is not the same compound as the vitamin D found in commercial vitamin supplements or added to food products such as milk or cereal.

Calcipotriene acts not only to inhibit cell proliferation and enhance cell differentiation in the skin of patients with psoriasis, but also appears to affect the substances in skin that generate the increased growth of localized cells. In several well-designed, short-term studies in adults, the efficacy of calcipotriene ointment (50 micrograms twice daily) was similar or superior to the efficacy of several other antipsoriatic agents in adult patients with mild to moderate psoriasis. Calcipotriene is generally well tolerated in short- and long-term studies in adult patients, with the major side effect being irritation. In addition, calcipotriene ointment proved benefits in combination with other topical, phototherapy, or systemic antipsoriatic treatments, including reducing the dosage and/or duration of some of these treatments and potentially improving their benefit to risk ratio. A recent study involving 972 psoriasis patients showed that calcipotriol (another name for calcipotriene) combined with betamethasone dipropionate (a corticosteroid) ointment provided more effective clearance of psoriasis lesions over a twelve week period than calcipotriene alone. All told, calcipotriene ointment is valuable as a first- or second-line therapy option alone or in combination with other antipsoriatic agents for severe psoriasis. Other forms of vitamin D3 creams include calcitriol and tacalitol.

Topical corticosteroids: Cortisone creams have been used for years as the first-step approach in the treatment of psoriasis, and are available in a wide variety of textures (from ointments to gels) and concentrations. Cortisones reduce inflammation, itching, and potentially slow skin cell proliferation. They are often used successfully with other psoriasis treatments. However, the more powerful the corticosteroid, the higher the risk of more severe side effects, which include burning, irritation, dryness, acne, thinning of the skin, dilated blood vessels, and loss of skin color.

Less potent topical steroids are often used for mild to moderate psoriasis, saving the high-potency versions for more severe conditions. An effective regimen uses high-potency cortisones, such as halobetasol (Ultravate), daily until the psoriasis plaque flattens out, after which the medication is applied only on the weekends. Another high-potency corticosteroid, mometasone (Elocon), needs to be administered only once a day and is as effective, or more effective than other corticosteroids while having a lower risk of severe side effects. These very potent drugs carry a small risk of causing hormonal problems for a period of time after the drug has been withdrawn. The larger the area treated with corticosteroids, the higher the risk, especially if the area is covered by heavy material or is bandaged. Also, in most cases, resistance to these drugs eventually develops.

Topical retinoids: such as Tazorac (active ingredient tazarotene) have been shown to have a positive effect on plaque psoriasis particularly in combination with other treatments. The manner in which it works is similar to potent topical steroids but with the advantage of a longer periods of relief during treatment and no detrimental side effects or damage to skin. In addition, combining tazarotene with topical steroids not only provides better treatment but also reduces the skin-thinning side effects of corticosteroid use. Tazarotene is also available as an oral prescription, though studies comparing systemic to topical application of this drug are lacking. As with other retinoids, tazarotene is not recommended for use while pregnant.

Salicylic acid: Often called beta hydroxy acid, salicylic acid is sold over the counter in strengths of 1.8% to 3%, but prescription strengths of 6% are often recommended in the treatment of psoriasis. Because it is an exfoliant, it can soften and remove scaly skin layers of psoriatic lesions. Removing these built-up skin layers is important because it allows other topical medications to better penetrate skin. Also, because of salicylic acid's chemical relationship to aspirin, it has anti-inflammatory properties which reduce the redness associated with psoriasis. Salicylic acid is available in many forms, and it is often combined with other topical medications to enhance their effectiveness in the treatment of psoriasis.

Systemic Treatments

Methotrexate: Methotrexate is an immune-modulating drug known for its ability to reduce the uncontrolled overproduction of cells. It is an established and highly effective systemic treatment for severe psoriasis and has been widely used during the last three decades. Methotrexate works by binding to an enzyme involved in the quickened growth of cells, and also slows down the growth of skin cells that leads to psoriasis. Thankfully, the long-term adverse effects of methotrexate are well known. The most frequent adverse effects that occur during methotrexate therapy are abnormal liver function test results, nausea, and gastric complaints. The most feared adverse effects are liver damage and the suppression of bone marrow activity. However, liver problems associated with methotrexate are related to a high cumulative dose. This means that rotating types of therapy or using methotrexate intermittently instead of continuously can reduce the risk. Most people tolerate low-dose methotrexate therapy relatively well, provided they work closely with their physician and watch carefully for adverse effects and drug interactions during treatment. The long-term clinical efficacy and relative safety of methotrexate remain impressive.

Methotrexate is not recommended for women who are or plan to become pregnant.

Cyclosporin (trade name Neoral): A strong immune-suppressant drug, cyclosporin is a primary medication used to prevent the rejection of transplanted organs. For psoriasis, cyclosporin acts by reducing inflammation in the skin and reducing cell proliferation by blocking immune factors (T-cell lymphocytes) that are likely generating the problem. It was FDA-approved for psoriasis in 1997, with the proviso that it not be used for more than a year at a time. Studies have shown cyclosporin to be highly effective and well tolerated in short-term treatment of severe psoriasis, including on the nails. However, this is a serious medication. Temporary side effects of cyclosporin can include headaches, gingivitis, joint pain, gout, body-hair growth, tremors, high blood pressure, kidney problems, and fatigue. Of serious concern is the National Toxicology Program's Eighth Report on Carcinogens, 1998, which warns that cyclosporin is "known to be a human carcinogen based on studies in humans." All of these factors must be weighed and carefully assessed before deciding on this course of treatment. Generally, cyclosporin therapy is reserved for use when other treatments have failed.

Acitretin (Soriatane), and isotretinoin (formerly known as Accutane) are oral retinoids. Acitretin is similar to isotretinoin, except that acitretin is the only retinoid approved by the FDA for use in the treatment of psoriasis. Isotretinoin is approved by the FDA for use in treating acne. How retinoids work in the treatment of psoriasis is not completely understood, although they are thought to block the overproduction of skin cells.

Neither of these retinoids are to be used when a woman is pregnant because all systemic retinoids have strong potential to cause major fetal abnormalities, including neurological and skeletal deformities. It is essential that effective contraception be used for at least one month before and throughout treatment. Severe fetal abnormalities do occur if a woman is or becomes pregnant while taking either acitretin or isotretinoin, but because isotretinoin doesn't remain in the system for long after you are finished with treatment, an extended waiting period is not required before becoming pregnant. Specifics regarding how long to wait after treatment before considering having a baby should be discussed with your physician. In contrast, acitretin can remain in the body up to three years following treatment. Therefore, it is imperative that pregnancy not occur during this time. If you are planning to conceive, discuss the pros and cons of acitretin versus isotretinoin with your physician.

Important note: Women of childbearing age should not consume alcohol during and for two months following treatment with acitretin. Alcohol can cause this drug to convert to a form that may remain in the body indefinitely. Other side effects associated with oral tretinoin therapy include dry skin and lips, and, to a lesser extent, liver damage and, potentially, depression.

Etanercept (trade name Enbrel): An interesting addition in the treatment of psoriasis is the antitumor medication Etancercept. Normally used to treat rheumatoid arthritis, Etanercept also appears to be a promising agent that can be used in combination therapy for the treatment of psoriasis. Six months of treatment (consisting of one or two injections per week) typically lead to a significant improvement in psoriasis symptoms. It is generally well-tolerated, with the most common side effect being a reaction at the injection site.

5-fluorouracil (brand name Efudex): Chemotherapy agents such as 5-fluorouracil may be effective in the treatment of psoriasis affecting the nails. Psoriatic-affected nails are quite common for those with psoriasis—up to 50% of those with psoriasis have it in their nails, too. There is no consistently effective treatment for psoriasis of the nail, though there are a handful of studies showing a topically applied 5% 5-fluorouracil cream can be beneficial.

Infliximab (trade name Remicade): Used to treat Crohn's disease and rheumatoid arthritis, Infliximab also is used for those with some forms of psoriasis after receiving FDA approval in late 2006. It is an injectible drug composed of antibodies derived from mice and humans. Results are often seen within 2 weeks, with lesion improvement considered excellent. Adverse effects include reactions at the site of injection (in clinical trials, 19% of subjects had such a reaction), fever, chest pain, chills, hypo- and hypertension, and shortness of breath. The most serious side effects are reactivation of tuberculosis in patients who have had this illness and the potential development of lymphomas. Although a clear causative factor has not been established, the theory is that immunosuppressive drugs such as Infliximab "provide a biologic basis for concern and justification for the initiation of additional epidemiological studies to formally evaluate this possible association." This medication clearly has strong potential to quickly alleviate the symptoms of psoriasis, but its side effects should be carefully discussed with your physician.

Alefacept (trade name Amevive): One of the first biologic drugs approved by the FDA specifically to treat moderate to severe plaque psoriasis this drug works by reducing the number of immune-activated T-cells in the skin, thus significantly reducing the major cause of psoriasis. It is administered by your physician via once a week injections for a period of 12 weeks. After this, the treatments are suspended in order to observe changes in the skin. If results are positive (meaning symptoms regress) further treatment is not needed until symptoms return and remissions of up to seven months are not uncommon. Because Alefacept suppresses the immune system in order to relieve psoriasis symptoms, side effects include an increased risk of infection or other potentially serious problems including an increased risk of cancer. Therefore, your physician must monitor your progress while on this medication, a process that includes weekly blood tests, usually done at or shortly after the time of each injection. The purpose of this is to make certain that T-cells and other immune system cells are not suppressed to the point that your general health is compromised.

Efalizumab: Similar to Alefacept, Efalizumab is FDA-approved for the treatment of psoriasis. It works by preventing the migration of immune-activated T-cells from the lymph nodes into the skin. By doing so, the inflammatory response that leads to symptoms of psoriasis is kept in check. It is important to note that while this drug blocks T-cell migration to skin, it does not reduce the number of T-cells in the body. Unlike alefacept, efalizumab can be self-injected in the comfort of your own home. It should be administered on a weekly basis. After three to six months of treatment, the majority of psoriasis patients experience significant reduction of symptoms. Results last up to three months in greater than 50% of patients, and this drug is typically well-tolerated. In contrast to Alefacept, Efalizumab does not cause immunosupression, though the period of remission does not last as long as what can take place with Alefacept. In clinical trials, it was noted that some patients experienced an immediate flaring up of symptoms once the medication was stopped.

Combination Therapy

PUVA: The most typical combination therapy for psoriasis is something called PUVA. PUVA is an abbreviation combining a prescription medication called Psoralen and exposure to ultraviolet light A (UVA). It is also called "photochemotherapy." The drug Psoralen, which can be taken orally as a pill or applied topically to the skin, makes the skin more sensitive and receptive to the wavelength of UVA light (320 to 400 nanometers). This combination suppresses the growth of abnormal skin cells. PUVA can eliminate or dramatically reduce psoriatic lesions for the majority of people who use it, and there is evidence it can provide extended remissions. The catch? Psoralen and UVA light are phototoxic and carcinogenic. Getting rid of psoriasis can mean a lot, but putting your skin at risk for premature aging and cancer may be trading one problem for another.

PUVA therapy brings with it an increased risk for squamous cell carcinoma among those who have fair skin and endure more than 200 treatments (not an unheard of number given that even with treatment psoriasis is a chronic skin disorder). Despite large scale international studies, evidence about whether or not PUVA therapy increases the risk of malignant melanoma (the most serious form of skin cancer) is conflicting.

In light of the risks involved, PUVA should be considered only for extreme or disabling psoriasis, after other treatments have failed. Although the risks to skin are considerable, it should be noted that compared to UVB phototherapy, PUVA treatments were shown (via a 100-person randomized study) to clear psoriasis symptoms in a greater number of patients and with fewer treatments (16 PUVA treatments vs. 25 UVB treatments). Further, six months after treatment, 35% of patients treated with PUVA were still in remission compared to just 12% of UVB-treated psoriasis patients .

All of the above treatments, both topical and oral, are often used in varying combinations for the best results. Frequently, several combination treatments are used in rotation to reduce the potentially harmful side effects of each one. Discovering whether any of these will work for you, alone or in combination, takes patience and a systematic, ongoing review and evaluation of how your skin and health are doing. Successful treatment, as is true with all chronic skin disorders, requires diligent adherence to the regimen and a realistic understanding of what you can and can’t expect. It is also important to be aware of the consequences of the varying treatment levels.

For more information on the current status of available treatments, visit the Web site for the National Psoriasis Foundation (NPF) at

Skin Care for Psoriasis

It won't come as a surprise to anyone dealing with psoriasis that over-the-counter or "traditional" skin-care products are incapable of curing or minimizing outbreaks. Still, if you have psoriasis, you may be wondering if there are any pointers to follow while shopping for skin-care products. Absolutely!. However, rather than psoriasis-specific guidelines, these tips fall under the category of general skin care so that you don't use products that make the problem worse.

All the basic skin-care needs are important for those with psoriasis, with an emphasis on only using products free of fragrance and irritating ingredients. Treating your skin to a routine of gentle cleansing, sun protection (discussed with your physician), and using a moisturizer loaded with antioxidants and anti-inflammatories will keep psoriasis lesions from looking or feeling worse and allow them to respond better to topical and systemic treatments. As long as everything you use is gentle, you will want to select products based on your skin type—oily, dry, or combination. Paula's Choice is one of the few truly fragrance-free, gentle skin-care lines that would be a consideration for those struggling with psoriasis.

The only skin-care exception for those with psoriasis is avoiding the use of topical scrubs over psoriasis-affected areas of skin. As discussed above, salicylic acid (BHA) is an option to control some of the symptoms of psoriasis. However, topical scrubs can be too abrasive and potentially irritating to use over psoriatic skin. Using AHA products is an option, but because these acids are not oil-soluble, they are not considered as effective as BHA for treating psoriasis lesions. Because Paula's Choice is fragrance and irritant-free, it is a great option for those with psoriasis.

Sources: The Journal of Immunology Online, January 2005, pages 164-173; PCI Journal, Volume 12, Number 5, 2004; Journal of Cutaneous Medicine and Surgery, December 2004, pages 1-2; Annals of the Rheumatic Diseases, November 4, 2004; Journal of Dermatology, October 2004, pages 798-801; British Journal of Dermatology, July 2004, pages 3-15; Cosmetic Dermatology, September 2004, pages 559-560; Clinical Experimental Dermatology, July 2004, pages 413-414; Toxicology and Applied Pharmacology, March 2004, pages 298-308; Journal of Dermatologic Treatment, January 2004, pages 14-22; British Journal of Dermatology, December 2003, pages 1250-1258; International Journal of Dermatology, October 2003, pages 834-838; Der Hautarzt, March 2003, pages 242-247; Dermatology Online Journal, February 2003, page 2; Israel Medical Association Journal, February 2003, pages 87-88; Photodermatology, Photoimmunology, and Photomedicine, August 2003, pages 164-168; Journal of Cosmetic Laser Therapy, June 2003, pages 101-106; British Journal of Dermatology, November 2002, pages 966-972; Skin Pharmacology and Applied Skin Physiology, September-0ctober 2002, pages 316-320; Clinical and Experimental Dermatology, March 2002, pages 99-103; National Institutes of Health, Department of Health and Human Services, Questions and Answers about Psoriasis, January 2002, online at; OTC Journal Newsletter, October 15, 2001, online at; JAMA Dermatol 2013;149(1):84-91; Uncomplicated Guide To Diabetes' Complications, 3rd Edition.

About the Experts

Paula Begoun is the best-selling author of 20 books on skin care and makeup. She is known worldwide as the Cosmetics Cop and creator of Paula's Choice. Paula's expertise has led to hundreds of appearances on national and international television including:

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The Paula's Choice Research Team is dedicated to busting beauty myths and helping you solve your skincare frustrations with research-supported expert advice—so you'll have the facts you need to take the best possible care of your skin.

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