In All Patients With Vitiligo, What is the Efficacy of Applying
Introduction
The use of medicaments to induce complete depigmentation may be considered in patients with vitiligo under certain situations.
Methods
There were no randomized controlled trials (RCTs). Case studies or consensus reports were considered.
Evidence Statements
Several products, some of which are marketed as cosmetics, have been used to reduce pigmentation of the skin. In certain countries such products are legally available over the counter; in others the products are available but not legally. These products may contain mercuric iodide (as in a germicidal soap), antiseptics containing phenolic derivatives and hydroquinone or related chemicals. In vitiligo, depigmentation may be considered as a therapeutic option when the patient has a naturally dark skin and has very obvious vitiligo extensively affecting cosmetically sensitive areas such as the face and backs of the hands. To induce depigmentation, the main method used has been the application of p-(benzyloxy)phenol (monobenzyl ether of hydroquinone, MBEH). There have been concerns about whether p-(benzyloxy)phenol is carcinogenic and it was banned from use in cosmetics in the EU in 2001. More recently, one study has examined the effect of topical 4-methoxyphenol (4MP) as a depigmenting agent.
Only two clinical trials that examine treatments aimed at depigmenting the normally pigmented skin in vitiligo were found. Both met the criteria for inclusion although one had only 13 subjects and the other 18. In both trials, it appears that only patients with generalized (symmetrical) types of vitiligo were included.
In the clinical trial described by Njoo etal.,[48] topical 4MP and the Q-switched ruby laser (QSRL) were used as the depigmenting agents. Topical 4MP produced total depigmentation in 11 of 16 subjects (69%; 95% confidence interval, CI 41-90%) with the onset of depigmentation within 4-12months. Of the 11, four had a recurrence of pigment after 2-36months. Side-effects of 4MP included mild burning or itching. Four of the five nonresponders to 4MP did depigment when treated using the QSRL. In the group treated using the QSRL, total depigmentation was found in nine of the 13 treated (69%; 95% CI 39-91%) with an onset within 7-14days. Four had recurrence of pigment after 2-18months. There were no side-effects in the QSRL group.
In an open study of p-(benzyloxy)phenol (MBEH),[49] 18 patients 'severely' affected by vitiligo (type of vitiligo not stated) were treated with the topical application of 20% MBEH. Eight achieved complete depigmentation after 10months and three had 'dramatic' depigmentation, but in three there was no effect at all (after 4months use).
Four papers on the management of vitiligo discuss the consensus view of the place of depigmentation treatment.[50,51,52,53] Expert consensus opinion concludes that patients with a dark skin type selected for depigmentation treatments must understand the cultural effects the depigmentation may have. It is usual to consider for depigmentation only subjects in whom the area of skin involved by vitiligo is extensive, usually taken to mean more than 50% of the skin surface area.[54] If there is extensive involvement of the cosmetically sensitive areas of the face and hands, and covering cosmetics are ineffective, depigmentation can be considered although it is usual to treat only the exposed sites.
Hydroquinones and related chemicals may cause side-effects. Irritation and occasionally contact dermatitis are recognized, as is the infrequent occurrence of ochronosis.[55] This had led to the banning of hydroquinones from over-the-counter products in Europe. Of more concern is the possibility of carcinogenesis from hydroquinones.[56] However, this is still a matter for debate.[55]
Evidence to Recommendations
In patients with extensive generalized forms of vitiligo, the topical use of MBEH and 4MP or the use of the QSRL are effective in inducing depigmentation. MBEH and 4MP can take a long time to have an effect, with onset of depigmentation often delayed until after 4months, and may be associated with local irritation and sometimes recurrence of pigmentation. With the QSRL, onset of the effect is much quicker and there are apparently fewer side-effects. This treatment may be preferred. However, there are few papers on this treatment and it is unwise to make a major recommendation based on one report.
Expert consensus recommends that patient selection is important in depigmentation treatment. It is vital that patients with a dark skin type understand the cultural implications. In general, depigmentation is undertaken only when the patient has more than 50% pigment loss in their skin due to vitiligo, or when the depigmentation is extensive in the cosmetically sensitive areas of the hands and face, when depigmentation of the exposed areas can be considered. This treatment is not recommended for children.
Recommendation
Depigmentation with p-(benzyloxy)phenol (MBEH) or 4MP should be reserved for adults severely affected by vitiligo (e.g. who have more than 50% depigmentation or who have extensive depigmentation on the face or hands) who cannot or choose not to seek repigmentation and who can accept the permanence of never tanning.
Grade of recommendation D Level of evidence 4
The British Journal of Dermatology. 2008;159(5):1051-1076. © 2008 Blackwell Publishing
Cite this: Guideline for the Diagnosis and Management of Vitiligo - Medscape - Nov 01, 2008.
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