In All Patients With Vitiligo, What is the Accuracy of a Scoring Index in Showing the Outcome of Common Treatments Compared With Simple Photography?
A problem when assessing efficacy of treatment for vitiligo is to quantify the response with an objective, valid and reproducible scoring system. The most important aspect of therapeutic response is how the patient feels about their vitiligo after the treatment (see above). Another, which may well include how a patient feels, is the degree of repigmentation that has occurred. When patients are asked 'what degree of repigmentation do you want?' the answer is 'complete'. However, 100% repigmentation is very rarely achievable and something less has usually to be accepted. Assessment of repigmentation in vitiligo studies usually involves the use of photography or sometimes, the 'rule of nines'. Both methods have serious drawbacks. Inevitably, photography is a two-dimensional medium. The rule of nines is an estimate of surface area. A better method is needed that takes into account more than just the surface area.
Only three papers were identified, two clinical trials and one observational study.
The vitiligo area-scoring index (VASI), based on the PASI score for psoriasis, is a quantitative tool that can be used to evaluate the extent of vitiligo based on a composite estimate of the overall area of depigmented patches at baseline and the degree of macular repigmentation within these patches. The VASI correlated well with physician and patient global assessments (P=0·05 and P=0·001, respectively). A problem with VASI is that it takes into account only the area of vitiligo, and not other factors.
The Vitiligo European Task Force (VETF) assessed vitiligo and treatment outcomes using a system that combines analysis of extent, stage of disease and disease progression. Extent is evaluated by the rule of nines; staging is based on cutaneous and hair pigmentation, and assessment of spreading is based on Wood's light examination. For extent, the investigators' correlations were very close (92% of evaluations were within 1% of the mean value). There were no patients with skin type VI in the study (20% of patients were skin type IV or V, which may not be representative for the U.K.). In addition, the measurements were not always consistent and no κ value was given for interobserver variability for extent of disease.
The use of digitized photographs subjected to morphometric computer analysis to delineate the degree of repigmentation has been described. This method seemed to be workable and compared well with physicians' visual evaluations.
Evidence to Recommendations
The response to treatments for vitiligo have typically been analysed using nominal binary scales in which the proportion of treated patients who achieve a specified degree of repigmentation is compared using nonparametric analysis based on physicians' assessment. The VETF tool adds two parameters, namely severity (staging) and progression (spreading). The VETF tool may give a more accurate assessment of vitiligo in research studies and seems to be the current gold standard but is impractical for routine clinic use. Digital photography with morphometric evaluation may be helpful in clinical trials.
The VASI and VETF tools offer a more accurate measure of disease extent than simple clinical photography alone (even when combined with computerized morphometry) and should be used in a research setting. Additionally, the VETF assesses severity and spreading.
Grade of recommendation D Level of evidence 2+
For routine clinical use, serial photographs should be used to monitor response to treatment in vitiligo.
Grade of recommendation C Level of evidence 4
Further research is needed to establish a simple, meaningful and reproducible method to monitor treatment response of vitiligo in the clinic and in clinical trials.
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.