Topical preparations–ointments, creams, gels, lotions, foams and the like that are applied directly to psoriasis plaques–are generally the first choice treatment for mild to moderate psoriasis. They are also used often by those with more severe psoriasis for “spot treatment” of hard-to-treat areas or those psoriasis patches that remain even while on other therapies.
Because they are used externally, topicals are typically the safest psoriasis treatments. Only a small fraction of the medication gets absorbed into the body, so side effects are confined, for the most part, to the skin (with important exceptions discussed below). Swallowed or injected medications, on the other hand, circulate throughout the body and can have unwanted effects on many organs. Approximately two-thirds of people with psoriasis can be treated with topical therapies alone. Interestingly, some of the side-effects problems that do occur with topical therapies occur when patients use them too extensively or too often; in an effort to limit their side-effects by using only topicals, these patients are actually overusing them and creating problems for themselves.
Keeping psoriasis in check usually requires long-term medication use. Patients who stop using topicals often see their psoriasis return in a few weeks or months. To minimize side effects, patients can alternate between brief periods of intensive treatment to bring flares under control and periods of lower dose or lower potency treatment to prevent recurrences.
Some topical medications come in a variety of formulations: ointment, cream, gel, lotion, solution, foam or mousse. Ointments are the most effective because they allow the best penetrations of the medication; however, they are also the greasiest. Creams are a less greasy though somewhat less effective option. Gels, lotions, solutions, and foams/mousses are good choices for use on the scalp.
Although topicals can be very effective, many patients find them difficult to use as directed. Applying the medication can be time-consuming; the preparations sometimes feel greasy or leave stains on clothing or bedding; and some, particularly coal tar, have an unpleasant odor. Patients need to work with their doctors to develop a treatment plan that they are comfortable following.
Research has found that many patients overstate how often they use topical treatments – leading some physicians to conclude a topical is not working when in reality, it may be failing because it is not being used as directed.
Name brand topical treatments that are not available in a generic version can be quote costly. [Several companies that market these more expensive options do offer programs to help people afford these treatments. Learn more here: Psoriasis Prescription Payment Assistance Programs.]
Topical anti-psoriasis agents in use today include: corticosteroids, vitamin D3 analogs, the retinoid tazarotene, coal tar, anthralin (aka dithranol), and salicylic acid.
Examples: clobetasol propionate (Class 1; Brand names: Cormax and Temovate), betamethasone dipropionate (Class 2; Brand name: Diprosone)
What are they? Corticosteroids are used to treat many conditions that are caused or worsened by inflammation, including arthritis, asthma, Crohn’s disease, and, of course, psoriasis. They are currently the most commonly prescribed topical medications for psoriasis. Corticosteroids are graded on a scale of 1-7 according to how potent they are with Class 1 being the most potent and Class 7 the least. Bringing psoriasis under control often requires short-term treatment with a Class 1 or Class 2 corticosteroid. Less potent corticosteroids can be used to maintain improvement. Weak corticosteroids (Class 6 or 7) are best for sensitive areas of the body such as the groin or face.
How are they administered? Topical corticosteroids are available as ointments, creams, gels, lotions, solutions, and mousses. The potency of a given medication can vary depending on the formulation. Ointments are generally the most powerful. To control a flare, patients typically use a Class 1 or 2 corticosteroid twice daily for 2-4 weeks. In between flares, patients can use a powerful corticosteroid less frequently (for example, only on weekends) or a less powerful corticosteroid daily. [Note: some dermatologists also offer cortisone shots directly into psoriasis patches, or plaques (and sometimes into specific joints targeted by psoriatic arthritis). You can read a proponent of these shots describe the procedure here.]
How well do they work? According to one review of data from multiple clinical trials, Class 1 corticosteroids are the most effective topical treatment for psoriasis. Treatment with a Class 1 medication for 2-4 weeks led to a 3 point (out of 12) improvement in the Total Severity Score (TSS), a measure of psoriasis severity that takes into account the redness, thickening, scaling, and itching of psoriasis plaques. Short-term treatment with a Class 2 corticosteroid led to a 1.6 point improvement in TSS; Class 2 corticosteroids were approximately equally effective as vitamin D3 analogs, tazarotene, coal tar, and anthralin.
Advantages: Corticosteroids work rapidly. They are also less likely to cause irritation than other topical psoriasis remedies.
Drawbacks: Corticosteroids can weaken or damage the skin where they are applied. Drug that is absorbed through the skin can interfere with the production of certain hormones in the body, causing symptoms such as fatigue and depression. This condition is known as suppression of the hypothalamic-pituitary-adrenal (HPA) axis. These side effects are more likely to occur in patients who use high potency corticosteroids for long periods of time. If patients abruptly stop using corticosteroids, they may experience a severe flare in the areas they had been treating. Gradually tapering the dose of corticosteroids is important to help prevent this problem. Finally, corticosteroids may become less effective with long term use (although recent research suggests this may be partly due to patients no longer applying them regularly rather than the durgs themselves no longer working).
How do they work?
Corticosteroids reduce inflammation by suppressing the activity of certain immune cells. They also slow the over-growth of skin cells that make up psoriasis plaques.
Vitamin D3 Analogs
Examples: calcitriol (Brand names: Vectical and Silkis), calcipotriene (aka calcipotriol; Brand name: Dovonex [and combined with a topical steroid as Taclonex]), tacalcitol (Brand names: Sold outside the US as Bonalfa and Curatoderm)
What are they? Vitamin D3 analogs are synthetic compounds that are chemically similar to naturally occurring vitamin D3 (aka calcitriol). Naturally occurring vitamin D3 has long been known to be effective against psoriasis; however, exposure to high levels can cause hypercalcemia (spelled abroad as hypercalcaemia, abnormally high calcium levels in the blood). The vitamin D3 analogs, first introduced in the 1990′s, have the same anti-psoriasis effects as natural vitamin D3 but much less of an effect on calcium levels, so they are safer.
How are they administered? Vitamin D3 analogs are available as ointments, creams, and solutions. The solution form is intended for use on the scalp. It usually takes about 8 weeks of twice daily use to see significant improvement in psoriasis symptoms. Patients can continue to use these medications twice daily to maintain improvement. The D3 analogs have been used continuously for up to 1.5 years in clinical trials without serious side effects.
How well do they work? Ultimately, vitamin D3 analogs are about as effective as Class 2 corticosteroids although they work more slowly. Eight weeks of treatment with vitamin D3 analogs produced a 1.6 (out of 12) point improvement in Total Severity Score (TSS). For comparison, 2-4 weeks of treatment with Class 2 corticosteroids also produced a 1.6 point improvement in TSS.
Advantages: Vitamin D3 analogs appear to be safe for long term use; and unlike corticosteroids, they remain effective even when used for long periods of time. Also, except for Taclonex, which also contains a topical steroid, vitamin D3 analogues offer patients a steroid-free treatment option.
Drawbacks: Vitamin D3 analogs cause irritation at the sites of application in about 15-20% of patients. For 2-3% of patients, the irritation is severe enough to force them to discontinue using the medication. Psoriasis usually returns within a couple of months after patients stop using the medication. High calcium levels in the blood is uncommon but something to keep an eye out for.
How do they work? Vitamin D3 analogs bind to vitamin D3 receptors located on the surface on certain types of cells. They most likely reduce psoriasis symptoms through their influence on the growth and activity of immune cells and skin cells.
(Brand names: Tazorac, Avage, Zorac)
What is it? The topical medication tazarotene belongs to a family of vitamin A related compounds known as retinoids. It is chemically similar to the systemic retinoid, acitretin (Soriatane). Tazarotene is sometimes used in the US off-label to treat psoriasis.
How is it administered? Tazarotene is available as a gel or cream. It is generally used once or twice daily in very small amounts–a pea sized amount can cover a palm-sized area of skin.
How well does it work? In terms of reducing psoriasis symptoms, tazarotene works about as well as Class 2 corticosteroids and vitamin D3 analogs. It works as quickly as corticosteroids, with improvement seen in 1-2 weeks. Tazarotene appears to be better than corticosteroids at producing sustained relief from symptoms. In one study, 12 weeks after discontinuing medication, 55% of patients who had used a corticosteroid experienced a worsening of their symptoms as compared to only 18% of patients who had taken tazarotene.
Advantages: Tazarotene works as quickly and as well as Class 2 corticosteroids with a lower rate of relapse when patients stop taking the medication. Outside of its devastating effect on pregnancy (see below), the side effects of tazarotene are few and fairly mild.
Drawbacks: Tazarotene causes severe birth defects, so it can never be used by patients who are pregnant or who might become pregnant. Women must have a thorough discussion with their physician about the potential for pregnancy before seriously considering tazarotene therapy. Tazarotene does not affect sperm so it is safe for men taking it to father children. About 30% of patients who use tazarotene experience skin irritation, although the newer cream formulations are thought to be less irritating than the gels.
How does it work? Retinoids bind to docking sites in cell nuclei known as retinoic acid receptors and affect the output levels of many genes in complex ways. Among other effects, retinoids influence the growth and development of skin cells, which may be important in controlling psoriasis.
(Brand name ointments: Fototar, Medotar, Psorent and many others; Brand name shampoos: Neutrogena T/Gel, Tegrin, and others)
What is it? Coal tar is a thick brown or black liquid that is a by-product of the processing of coal. It is an old and effective treatment for psoriasis, but it has always been associated with its strong odor and propensity to stain.
How is it administered? Coal tar can be used in the clinic or on an outpatient basis. In the clinic, topical coal tar is used together with ultraviolet B (UVB) light therapy in a regimen known as the Goeckerman treatment. For outpatient use, coal tar comes in many formulations including lotions, ointments, and shampoos. The amount of coal tar varies greatly in different preparations, from 0.5% to 5%. A less potent form of coal tar, liquor carbonis detergens or liquor carbonis distillate is available in concentrations up to 20%. Some coal tar products are available over the counter; others are prescription only. The details of use–how often the medication should be used, how long it should be left on the skin, and how long the medication should be used–also vary from product to product. Prices also vary dramatically for the same active ingredient, so buyer beware.
How well does it work? The Goeckerman treatment (coal tar plus UVB) is highly effective. A 3-4 week course of treatment produces a big improvement in about 90% of patients, and for many patients, the improvement lasts for a year or more. According to some studies, the effectiveness of over-the-counter coal tar products is similar to Class 2 corticosteroids, vitamin D3 analogs, and anthralin; however, in some head-to-head studies comparing coal tar to vitamin D3 analogs, the vitamin D3 analogs were superior.
Advantages: Though considered a carcinogen at some concentrations, coal tar has a long-established record as a safe and effective psoriasis treatment. It can be very helpful for patients who cannot use or don’t respond to other topical medications, and in some cases is relatively inexpensive.
Drawbacks: The Goeckerman treatment is expensive and time-consuming and is no longer readily available. Coal tar has a strong, unpleasant smell and stains clothing and bedding. Some patients using coal tar experience skin irritation or folliculitis (infection of the hair follicles). Coal tar sensitizes the skin to sunlight so patients using coal tar products have to be careful to avoid sunburn. Exposure to very high levels of coal tar in industrial settings has been associated with the development of cancer; however, there is no evidence that therapeutic doses of coal tar cause cancer.
How does it work? Nobody knows. Coal tar contains about 10,000 different chemicals, only 50% of which have been identified, and it is unclear which one(s) are active against psoriasis, let alone how they work.
Anthralin (aka dithranol)
(Brand names: Psoriatec and others)
What is it? Like coal tar, anthralin is an old treatment for psoriasis that has fallen out of favor in recent years because it is messy and difficult to use. Unlike coal tar, which is a complex mixture of substances, anthralin is a single chemical that was originally purified from the bark of a South American tree. Nowadays, it is commercially synthesized. It is known as anthralin in the United States and as dithranol internationally.
How is it administered? Anthralin is available in ointment or cream form. It is usually applied to psoriasis plaques for short periods of time (5-30 minutes) and then washed off. The concentration of the medication and the length of exposure can be gradually increased over several weeks. Patients usually use anthralin for a number of weeks until their skin improves significantly and then discontinue use. Anthralin can also be used together with UVB light therapy. This procedure is more common in Europe and is known as the Ingram therapy.
How well does it work? Anthralin works about as well as coal tar. In some studies it was as effective as vitamin D3 analogs. It doesn’t work as quickly as corticosteroids, but improvements can last for many months after patients stop using it.
Advantages: Anthralin can produce long lasting improvements in psoriasis symptoms. It may help patients who have specific reasons for not using other topical treatments.
Drawbacks: Anthralin stains skin, clothing, and other objects (like bathtubs) purple. A newer, less staining formulation of anthralin called Micanol is available. Anthralin is very irritating and must be washed away carefully after brief (5-30 minute) treatment periods.
How does it work? It is not known for sure how anthralin works, but it may block the overgrowth of skin cells in psoriasis plaques by interfering with the cell’s ability to generate energy.
(Brand names: Neutrogena Healthy Scalp Dandruff Shampoo, T/Sal and others)
What is it? Salicylic acid is a keratolytic, a medication that causes peeling of the outer layer of the skin. It reduces scaling of psoriasis plaques. Because reducing scale can help other medications penetrate better, salicylic acid is often used in combination with other agents, for example, corticosteroids. Salicylic acid is also used for other conditions, including dandruff, acne, warts and corns.
How is it administered? Salicylic acid is available in a large number of over the counter ointments, lotions, gels, creams, and shampoos. However, effective psoriasis treatment often requires prescription strength salicylic acid (up to 10%), which is mixed into an ointment base by a pharmacist. It is most commonly used together with a topical corticosteroid.
How well does it work? Salicylic acid is not very effective on its own. Its main purpose is to enhance the penetration, and consequently the effectiveness, of other medications, usually corticosteroids. However, in one clinical trial, salicylic acid alone was helpful in treating scalp psoriasis. Salicylic acid is more effective than the other common keratolytics, urea and lactic acid.
Advantages: Salicylic acid is the most effective keratolytic. It is very useful for helping other medications penetrate thick, scaly patches of psoriasis.
Drawbacks: Salicylic acid can be toxic if applied to more than 20% of the body’s surface area. Because salicylic acid preparations are often individually mixed by pharmacists, there can be variations in quality and a higher chance of medication error. Salicylic acid inactivates the vitamin D3 analog, calcipotriene so these medications should not be used together.
How does it work? Salicylic acid causes softening and separation of the outer layer of the skin.
Psoriasis patients often get the best results from combining topical therapies. One common combination is corticosteroids with salicylic acid (see above: Salicylic Acid).
Another is Class 1 corticosteroids with the vitamin D3 analog, calcipotriene. The corticosteroid and the calcipotriene are each applied once a day at different times. The corticosteroid brings about fast results and reduces irritation caused by the calcipotriene. The calcipotriene helps the patient avoid adverse effects from corticosteroid use by lowering the dose of corticosteroid needed to keep psoriasis in check. After a flare is under control, patients can gradually stop using the corticosteroid and continue using the calcipotriene. Taclonex is an ointment that contains both calcipotriene and the corticosteroid betamethasone dipropionate. While effective, it is also expensive.
Other over-the-counter ingredients:
Psoriasis patients seeking relief will try just about anything. Some have found relief from products including aloe, oatmeal, zinc pyrithione, salt baths from the Dead Sea and elsewhere, moisturizers, capsaicin, and of course, the inexpensive workhouse petroleum jelly. If you have found a product that helps you, let us know.