Skin Conditions and Complementary Health Approaches: What the Science Says

Atopic Dermatitis

According to the American Academy of Dermatology’s clinical practice guidelines, there is inconsistent to no evidence to recommend the use of fish oils, evening primrose oil, borage oil, multivitamin supplements, zinc, vitamin D, vitamin E, and vitamins B12 and B6 for the treatment of atopic dermatitis. Further, the guidelines state that the use of probiotics/prebiotics for the treatment of patients with established atopic dermatitis is not recommended because of inconsistent evidence.

What Does the Research Show?

• Dietary Supplements (Oral). A 2012 Cochrane review of 11 randomized controlled trials of dietary supplements (e.g., fish oil, vitamin D and vitamin E, vitamin B6, sea buckhorn oil, hempseed oil, sunflower oil, docosahexaenoic acid (DHA), selenium, and zinc sulfate) found no convincing evidence of their benefit for atopic eczema. The American Academy of Dermatology’s clinical practice guidelines for the treatment of atopic dermatitis states that “there is inconsistent to no evidence to recommend the use of fish oils, evening primrose oil, borage oil, multivitamin supplements, zinc, vitamin D, vitamin E, and vitamins B12 and B6 for the treatment of atopic dermatitis.”
  • Vitamin D (Oral). A 2019 systematic review and meta-analysis of 16 studies found that vitamin D supplementation showed clinically relevant improvements in participants with atopic dermatitis at a weighted average dose of 1500–1600 IU for up to 3 months. The reviewers noted that further research is required to establish the efficacy of vitamin D2 versus D3 in reducing AD severity, as well as the effects of vitamin D supplementation on infection rates, including superinfections and topical steroid usage.
• Probiotics (Oral). The American Academy of Dermatology’s clinical practice guidelines for treatment of atopic dermatitis state that “the use of probiotics/prebiotics for the treatment of patients with established atopic dermatitis is not recommended because of inconsistent evidence (Level of Evidence II; Strength of Recommendation B)."
  • There are conflicting data on the efficacy of probiotics for atopic dermatitis in children; overall, evidence suggests that probiotics may be effective for some, but not all, children with atopic dermatitis.
  • A 2021 multicenter, randomized, double blind, placebo-controlled study evaluated the effectiveness of Lactobacillus rhamnosus and Lactobacillus casei strains in children under 2 years of age with atopic dermatitis and a cow's milk protein allergy. After the 3-month intervention, both the probiotic and placebo groups showed a significant decrease in extent and severity of eczema scores, which was maintained 9 months later. The percentage of children who showed improvement was significantly higher in the probiotic than in the placebo group.
  • A 2013 systematic review of 21 randomized controlled trials involving 6,859 participants, which included infants or individuals who were either pregnant or breastfeeding, investigated whether nutrient supplementation with probiotics, prebiotics, formula, or fatty acids prevents the development of atopic dermatitis or reduces the severity of the condition in newborns to children under 3 years of age. Data showed that certain types of nutrient supplementation may be an effective method in preventing atopic dermatitis or decreasing its severity. The best evidence, the reviewers found, lies with probiotics supplementation in infants and in pregnant or breastfeeding individuals in preventing the development and reducing the severity of atopic dermatitis.
• Probiotics (Topical). A 2021 systematic review of seven studies concluded that preliminary data suggest emollients containing probiotics and bacteria-derived preparations are safe for use in atopic dermatitis; however, well-designed clinical trials are needed to establish the efficacy of topical probiotics on disease severity.
• Primrose Oil and Borage Oil (Oral). A 2013 Cochrane review of 27 randomized controlled trials involving a total of 1,596 participants found that evening primrose oil and borage oil taken orally had no clinical benefit for the treatment of atopic eczema.
• Chinese Herbal Medicine (Oral and Topical). Another 2013 Cochrane review of 28 randomized controlled trials involving a total of 2,306 participants found no conclusive evidence that oral or topical Chinese herbal medicine could reduce the severity of atopic eczema in children or adults. A 2016 review of 70 studies found some evidence that herbal preparations can have real effects in the treatment of atopic dermatitis; however, the reviewers concluded that the complexity of these preparations and their potential risks make this area inscrutable for most practitioners. They also noted that while there is real evidence of positive effect, there are too many unanswered questions to warrant routine clinical use of such herbs, and significant further research is needed before widespread clinical adoption can occur.

Safety

• Patients considering the use of Chinese herbal medicine, especially for children, should use caution as they can be potentially hazardous. A 2013 review noted that these medications are easily accessed and not monitored by the U.S. Food and Drug Administration, and that some topical Chinese herbal medicines have been found to include high concentrations of dexamethasone.

Psoriasis

There is some evidence that fish oil, Dead Sea climatotherapy, and the topical herbs Mahonia aquifolium and indigo naturalis may be beneficial for the treatment of psoriasis.

What Does the Research Show?

• Traditional Chinese medicine (Oral). There is some evidence that has shown that the combination of traditional Chinese medicine taken orally with conventional treatments for psoriasis is more efficacious than conventional treatment alone.
• Dietary Supplements (Oral).  A 2015 review noted that there has been consistent evidence supporting the efficacy of fish oil supplementation in patients with psoriasis; however, a 2019 meta-analysis of 13 randomized controlled trials involving a total of 625 participants found that fish oil supplementation did not significantly reduce the severity of psoriasis when assessed by Psoriasis Area and Severity Index score. There is conflicting evidence for vitamin D, B12, and selenium supplementation.
• Herbal Medicine (Topical). A 2018 review of eight studies found that Mahonia aquifolium leads to a statistically significant improvement of symptoms in psoriasis and atopic dermatitis with minimal side effects. A 2017 randomized, double-blind, placebo-controlled clinical study of 24 participants with moderate plaque psoriasis found that compared with placebo, indigo naturalis–treated patients had significant improvement in Psoriasis Area and Severity Index (PASI) scores from baseline. There is a smaller amount of evidence for aloe vera, neem, and extracts of sweet whey.
• Vitamin D (Topical). A 2013 Cochrane review of 177 studies involving a total of 34,808 people found that topical vitamin D products were superior to placebo, and had similar effects to topical corticosteroids when applied to the body. However, corticosteroids were superior to vitamin D for scalp psoriasis. Treatment that combined topical vitamin D with a corticosteroid was more effective than topical vitamin D alone and more effective than the topical corticosteroid alone.
• Climatotherapy. There is evidence from controlled trials that Dead Sea climatotherapy can improve psoriasis and induce lasting remissions; however, research on other locations of climatotherapy have provided little evidence.
• Light Therapy. A 2019 review concluded that based on the efficacy and safety, NB-UVB is the gold standard for treating psoriasis and atopic dermatitis, and the UVB excimer laser and excimer lamp might be the best option for clearing localized therapy-resistant lesions. The reviewers noted that home UV phototherapy systems might improve treatment adherence. However, they also noted that vascular lasers, intense pulse lights, and low-level light treatment cannot currently be recommended for the treatment of inflammatory skin diseases because of the lack of well-controlled studies. Findings from a 2015 randomized controlled trial of 21 patients with plaque psoriasis suggest that moderate to severe plaque psoriasis should show a therapeutic response to orally administered Curcuma longa extract if activated with visible light phototherapy. A 2015 randomized controlled trial of 47 patients with mild psoriasis vulgaris evaluated the safety and efficacy of long-term UV-free blue light treatment and found that participants receiving blue light treatment had a significant improvement compared to the control.

Safety

• Some Chinese herbal medicines have been shown to be contaminated with heavy metals or corticosteroids. Other safety concerns include systemic toxicity or contact dermatitis from herbal supplements.
• Ultra-violet light exposure increases the risk of melanoma and non-melanoma skin cancers, so the benefits of climatotherapy should be carefully weighed against the risks for each patient.
• Vitamin D products may cause “local adverse events,” such as skin irritation and burning.

Acne

According to the American Academy of Dermatology’s clinical practice guidelines for the treatment of acne, there are currently very limited data regarding the safety and efficacy of herbal and other complementary therapies to recommend their use.

What Does the Research Show?

• Tea Tree Oil, Bee Venom (Topical). A 2015 Cochrane review of 35 randomized controlled trials involving 3,227 participants concluded that there is some low-quality evidence from single trials that topical tea tree oil and bee venom may reduce total skin lesions in acne, but there is a lack of evidence from the review to support the use of other complementary health approaches, such as herbal medicine, acupuncture, or wet-cupping therapy. A 2019 review of four studies involving pediatric patients with acne concluded that overall, the quality of evidence to support tea tree oil in pediatric acne vulgaris is low.
• Barberry Extract (Oral). Other herbal agents, such as oral barberry extract, showed some beneficial effects in a 2012 randomized controlled trial of 49 adolescents with moderate-to-severe acne.
• Zinc (Oral). There have been several randomized controlled trials that have examined oral zinc supplementation in the treatment of acne in teenagers and young adults; some have shown efficacy over placebo, while others did not.
• Gugulipid (Oral). In one study, gugulipid, an extract of gum guggul, given twice daily (25 mg) was compared to oral tetracycline 500 mg twice daily for treatment of nodulocystic acne in patients aged 16 to 25 years. Both interventions resulted in improvement in acne lesions, and the percentage reduction in inflammatory lesions was similar without a statistically significant difference.
• Probiotics (Oral and Topical). A 2020 review found that probiotics as adjunct therapy (topical or oral) can play an effective role in managing acne by directly preventing the growth of opportunistic bacteria or by controlling inflammation. The reviewers recommended that interventional studies be conducted using large samples and long follow-ups to demonstrate the effectiveness of these beneficial bacteria and pinpoint their other potential advantages and disadvantages.

Safety

• In a 2012 study, oral aqueous extract of barberry was well tolerated, and no notable complications or side effects were reported.
• Tea tree oil contains varying amounts of 1,8–cineole, a skin irritant. Products with high amounts of this compound may cause skin irritation or contact dermatitis in some individuals. Oxidized tea tree oil may trigger allergies more than fresh tea tree oil.
• Tea tree oil should not be swallowed. Poisonings, mainly in children, have caused drowsiness, disorientation, rash, and ataxia. Topical use of diluted tea tree oil is generally considered safe for most adults. Pruritus, burning, stinging, scaling, itch, redness, and dryness have been reported.
• There is a potential for adverse effects from herbal medicines. Patients considering the use of Chinese herbal medicine, especially for children, should use caution as they can be potentially hazardous. A 2013 review noted that these medications are easily accessed and not monitored by the U.S. Food and Drug Administration, and that some topical Chinese herbal medicines have been found to include high concentrations of dexamethasone.

Impetigo

There is insufficient evidence to either recommend or dismiss herbal treatments for impetigo, including tea tree oil, garlic, coconut oils, tea effusions, and Manuka honey.

What Does the Research Show?

• Herbal Medicine (Oral and Topical). A 2003 review of seven randomized and non-randomized studies examining both oral and topical herbal medicines for the treatment of bacterial infections, including impetigo, found some positive results reported for a topical ointment containing tea leaf extract. However, the reviewers concluded that the clinical efficacy of none of the herbal medicines has so far been demonstrated.

Safety

• There is a lack of safety data on herbal medicines for the treatment of impetigo.
• Patients should be encouraged to maintain proper wound care and hand washing and avoid contact with others as the infection can spread.

Rosacea

Although some natural products have shown promise for improving symptoms of rosacea, there is insufficient evidence to support the use of many of these products for rosacea.

What Does the Research Show?

• Plant Extracts (Oral and Topical). A 2015 systematic review of phytochemical and botanical therapies for rosacea found that several botanical therapies may be promising for rosacea symptoms, with several plant extracts and phytochemicals improving facial erythema and papule/pustule counts caused by rosacea. However, many of the studies included in the review were not methodologically rigorous.
• Azelaic Acid (Topical). A 2010 review of natural products had similar findings, but noted that based on two randomized trials, topical azelaic acid—a naturally occurring 9-carbon acid found in whole grain cereals and animal products—may provide some benefit for symptoms of rosacea.

Safety

• The 2015 systematic review of various phytochemical and botanical therapies found mild adverse reactions, such as transient burning or pruritus, and noted that several botanicals commonly used for rosacea have not been studied clinically and these may have more significant side effect profiles.
• A 2010 review of two studies found azelaic acid to be generally safe, with mild and transient local adverse reactions, and no difference between azelaic acid and placebo.