Psoriasis is a common, poorly understood condition that affects primarily the skin but may also affect nails. A related condition, psoriatic arthritis, affects joints.
The fact that some people with psoriasis improve while taking prescription drugs that interfere with the immune system suggests that the disease might result from a derangement of the immune system. A dermatologist should be consulted to confirm the diagnosis of psoriasis.
What are the symptoms of psoriasis?
The hallmark symptom of psoriasis is well-defined, red patches of skin covered by a silvery, flaky surface that has pinpoint spots of bleeding underneath if scraped. The patches typically appear during periodic flare-ups and are in the same area on both sides of the body. In some people with psoriasis, the fingernails and toenails may have white-colored pits, lengthwise ridges down the nail, or yellowish spots, or may be thickened or may separate at the cut end.
Dietary changes that may be helpful for psoriasis
Ingestion of alcohol has been reported to be a risk factor for psoriasis in men but not women.1 2 It would therefore be prudent for men with psoriasis to restrict their intake of alcohol or avoid it entirely.
Anecdotal evidence suggests that people with psoriasis may improve on a hypoallergenic diet.3 Three trials have reported that eliminating gluten (found in wheat, rye, and barley) improved psoriasis for some people.4 5 6 A doctor can help people with psoriasis determine whether gluten or other foods are contributing to their skin condition.
Nutritional supplements that may be helpful for psoriasis
Fumaric acid, in the chemically bound form known as fumaric acid esters, has been shown in case studies,7 preliminary trials8 9 10 and double-blind trials11 12 13 to be effective against symptoms of psoriasis. However, because fumaric acid esters can cause significant side effects, they should be taken only under the supervision of a doctor familiar with their use. Nevertheless, these side effects have been reported to decrease in frequency over the course of treatment and, if they are closely monitored, rarely lead to significant toxicity.14
In a double-blind trial, fish oil (10 grams per day) was found to improve the skin lesions of psoriasis.15 In another trial, supplementing with 3.6 grams per day of purified eicosapentaenoic acid (EPA, one of the fatty acids found in fish oil) reduced the severity of psoriasis after two to three months.16 17 That amount of EPA is usually contained in 20 grams of fish oil, a level that generally requires 20 pills to achieve. However, when purified EPA was used in combination with purified docosahexaenoic acid (DHA, another fatty acid contained in fish oil), no improvement was observed.18
Additional research is needed to determine whether fish oil itself or some of its components are more effective for people with psoriasis. One trial showed that applying a preparation containing 10% fish oil directly to psoriatic lesions twice daily resulted in improvement after seven weeks.19 In addition, promising results were reported from a double-blind trial in which people with chronic plaque-type psoriasis received 4.2 g of EPA and 4.2 g of DHA or placebo intravenously each day for two weeks. Thirty-seven percent of those receiving the essential fatty acid infusions experienced greater than 50% reduction in the severity of their symptoms.20
Supplementing with fish oil also may help prevent the increase in blood levels of triglycerides that occurs as a side effect of certain drugs used to treat psoriasis (e.g., etretinate and acitretin).21
Folic acid antagonist drugs have been used to treat psoriasis. In one preliminary report, extremely high amounts of folic acid (20 mg taken four times per day), combined with an unspecified amount of vitamin C, led to significant improvement within three to six months in people with psoriasis who had not been taking folic acid antagonists;those who had previously taken these drugs saw a worsening of their condition.22
Although some doctors have been impressed with the effectiveness of flaxseed oil (usually 1 to 3 tbsp per day) against psoriasis, there have been no published trials to support that observation.
The vitamin D that is present in food or manufactured by sunlight is converted in the body into a powerful hormone-like molecule called 1,25-dihydroxyvitamin D. That compound and a related naturally occurring molecule (1 alpha-hydroxyvitamin D3) have been found to reduce skin lesions when given orally to people with psoriasis.23 Topical application of these compounds has also been effective in some,24 25 26 27 but not all,28 29 trials. These activated forms of vitamin D are believed to help by preventing the excessive proliferation of cells that occurs in the skin of people with psoriasis. Because these potent forms of vitamin D can cause potentially dangerous increases in blood levels of calcium, they are available only by prescription. Toxicity is usually less of a problem with activated vitamin D applied topically than with activated vitamin D taken orally. The use of these compounds (under the supervision of a qualified dermatologist) may be considered in difficult cases of psoriasis. The form of vitamin D that is available without a prescription is unlikely to be effective against psoriasis.
Are there any side effects or interactions with psoriasis?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful for psoriasis
Cayenne contains a resinous and pungent substance known as capsaicin. This chemical relieves pain and itching by depleting certain neurotransmitters from sensory nerves. In a double-blind trial, application of a capsaicin cream to the skin relieved both the itching and the skin lesions in people with psoriasis.30 Creams containing 0.025 to 0.075% capsaicin are generally used. There may be a burning sensation the first several times the cream is applied, but this usually become less pronounced with each use. The hands must be carefully and thoroughly washed after use, or gloves should be worn, to prevent the cream from accidentally reaching the eyes, nose, or mouth and causing a burning sensation. The cream should not be applied to areas of broken skin.
A double-blind trial in Pakistan found that topical application of an aloe extract (0.5%) in a cream was more effective than placebo in the treatment of adults with psoriasis.31 The aloe cream was applied three times per day for four weeks.
In traditional herbal texts, burdock root was believed to clear the bloodstream of toxins.32 It was used both internally and externally for psoriasis. Traditional herbalists recommend 2 to 4 ml of burdock root tincture per day. For the dried root preparation in tablet or capsule form, the common amount to take is 1 to 2 grams three times per day. Many herbal preparations will combine burdock root with other alterative herbs, such as yellow dock, red clover, or cleavers. Burdock root has not been studied in clinical trials to evaluate its efficacy in helping people with psoriasis.
Although clinical trials are lacking, some herbalists use the herb, coleus, in treating people with psoriasis.33 Coleus extracts standardized to 18% forskolin are available, and 50 to 100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2 to 4 ml three times per day.
An ointment containing Oregon grape (10% concentration) has been shown in a clinical trial to be mildly effective against moderate psoriasis but not more severe cases.34 Whole Oregon grape extracts were shown in one laboratory study to reduce inflammation often associated with psoriasis.35 In this study, isolated alkaloids from Oregon grape did not have this effect. This suggests that there are other active ingredients besides alkaloids in Oregon grape. Barberry, which is very similar to Oregon grape, is believed to have similar effects. An ointment, 10% of which contains Oregon grape or barberry extract, can be applied topically three times per day.
Are there any side effects or interactions with psoriasis?
Refer to the individual herb for information about any side effects or interactions.
Holistic approaches that may be helpful for psoriasis
A preliminary trial treated 61 psoriasis patients with acupuncture that did not respond to conventional medical therapies. After an average of nine acupuncture treatments, 30 (49%) of the patients demonstrated almost complete clearance of the lesions, and 14 (23%) of the patients experienced a resolution for two-thirds of lesions.36 A controlled trial of 56 patients with psoriasis found, however, that acupuncture and “fake” acupuncture resulted in similar, modest effects.37 More controlled trials are necessary to determine the usefulness of acupuncture in the treatment of psoriasis.
Stress reduction has been shown to accelerate healing of psoriatic plaques in a blinded trial.38 Thirty-seven people with psoriasis about to undergo light therapy were randomly assigned to receive either topical ultraviolet light treatment alone or in combination with a mindfulness meditation-based stress reduction technique guided by audiotape. Those who received the stress-reduction intervention showed resolution of their psoriasis significantly faster than those who did not.
Hypnosis and suggestion have been shown in some cases to have a positive effect on psoriasis, further supporting the role of stress in the disorder.39 In one case report, 75% resolution of psoriasis resulted from using a hypnotic sensory-imagery technique.40 Hypnosis may be especially useful for psoriasis that appears to be activated by stress.