In All Patients With Vitiligo, What is the Efficacy of a Course of Khellin With Sunlight UVA or UVB Compared With PUVA or PUVA-sol in Terms of Progression, Area Reduction and Quality of Life Score?
Khellin is a naturally occurring furochromone which is a structural isomer of methoxsalen. In combination with UVA or sunlight khellin is reported to induce repigmentation of vitiliginous skin. The exact mechanism of action of khellin plus UVA in vitiligo is unknown.
Five papers were identified by the computer-assisted search strategy and all five are relevant to the question. However, none of these papers adhered strictly to an RCT design.
In a study comparing khellin or placebo both with natural sunlight, 12 of 30 in the khellin group showed >50% repigmentation compared with none in the control group. A left-vs.-right study of 72 patients compared khellin with UVA vs. UVA alone and concluded that repigmentation was due to the UVA, not the khellin. A left-vs.-right study compared khellin plus sunlight with vehicle plus sunlight in 41 patients and found no difference between the khellin and placebo groups. However, in a later study the same authors compared a khellin gel and UVA with UVA alone, finding that both groups responded but khellin plus UVA was superior to UVA alone (P<0·01). A study with 33 patients compared topical khellin plus UVA with PUVA, concluding that khellin plus UVA may induce repigmentation comparable with that induced by systemic PUVA, but required a longer duration.
Despite apparent initial promise, research in this area is inconclusive and at times contradictory.
There is currently insufficient evidence to recommend khellin with UV in the treatment of vitiligo.
Grade of recommendation D Level of evidence 3
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.