Herbal supplements
Several research teams have examined Ginkgo biloba as a possible treatment for vitiligo. This plant is native to China and has antioxidant and anti-inflammatory properties; its most common side effect is gastrointestinal distress. Because it entails a risk of coagulopathy, it may not be appropriate for patients receiving anticoagulant treatment, Dr. Elbuluk pointed out. In a double-blinded, randomized, controlled trial comparing ginkgo biloba alone with placebo in patients with vitiligo, treatment was associated with cessation of active disease in most patients, and more than 40% of patients receiving ginkgo biloba had 75% repigmentation or more.
Polypodium leucotomos, a fern native to Central and South America, protects against UV radiation damage, modulates the immune system, and has anti-inflammatory and antioxidant effects. It has a good safety profile and is well tolerated at a dose of 240 mg/day, she said. It sometimes causes gastrointestinal discomfort or pruritus. Several randomized, controlled trials in patients with vitiligo showed that supplementation with polypodium leucotomos improves repigmentation, particularly in photo-exposed areas, she noted.
Khellin is an extract from the Mediterranean khella plant that is thought to stimulate melanocyte proliferation and melanogenesis. Several studies have examined khellin supplementation in combination with phototherapy. Khellin can be administered orally or topically and appears to be more beneficial than sunlight or phototherapy alone in stabilizing disease or inducing repigmentation. Oral khellin can cause many side effects, including nausea, transaminitis, and hypotension, so researchers have been more interested in using topical khellin as a liposomal vehicle to improve drug delivery, Dr. Elbuluk said.
Minerals
Some patients with vitiligo have deficiencies in zinc and copper. Zinc is an antioxidant that aids wound healing, protects against free radicals, supports melanogenesis, and possibly prevents melanocyte death, but can cause gastrointestinal irritation. Copper, too, is an antioxidant and coenzyme involved in melanogenesis. One study compared topical steroid treatment with and without oral zinc supplementation. Dual treatment was associated with greater repigmentation, but the difference was not statistically significant. No studies have examined copper supplementation, she said.
L-phenylalanine, diet, and green tea
Investigators have proposed that the amino acid L-phenylalanine, a precursor to tyrosine in the pathway of melanin synthesis, might interfere with antibody production against melanocytes. This supplement is administered orally by weight, typically in conjunction with phototherapy or sunlight. Various studies have observed positive outcomes of L-phenylalanine combined with phototherapy or sunlight. L-phenylalanine tends to be safe and has been administered to children with vitiligo.
Many patients with vitiligo “have already tried diets by the time they come to me,” said Dr. Elbuluk. No controlled studies have analyzed the role of diet in the prevention or treatment of vitiligo, but case reports describe gluten-free diets in this population, including one report of a patient with celiac disease whose vitiligo improved after adoption of such a diet. Another case report described a patient without celiac disease who had refractory acrofacial vitiligo, which improved after the adoption of a gluten-free diet. Evidence supports a gluten-free diet for patients with celiac disease, but does not support this challenging diet for people without celiac disease, she pointed out.
Green tea includes catechins, which have antioxidant and anti-inflammatory properties. Its main component is epigallocatechin gallate (EGCG), which is thought to modulate T cell mediated responses. In one animal study, administration of EGCG delayed the onset of vitiligo and decreased the area of depigmentation in a mouse model. Although these findings are promising, clinical trials are needed to determine whether EGCG is beneficial in humans with vitiligo, said Dr. Elbuluk.
The literature on diets and supplementation as treatments for vitiligo has several shortcomings, with studies that used heterogeneous methodologies, and many that used nonstandard outcome measures that have not been validated. Sample sizes often are small, and many trials are uncontrolled. “These limitations make it harder to make sense of the data and have take-home conclusions,” Dr. Elbuluk said.
She had no disclosures.
SOURCE: Elbuluk N. AAD 19, Session S002.