A retrospective study of narrowband-UVB phototherapy for treatment of vitiligo in Malaysian patients.

Psoralen and ultraviolet light A (PUVA) was the mainstay of vitiligo treatment before the introduction of narrowband UVB(NB-UVB). Eighteen patients treated with NB-UVB in Hospital Kuala Lumpur were retrospectively analyzed. Eight patients had Fitzpatrick skin phototype III and 10 with phototype IV. The mean duration of disease was 7.3 +/- 5.4 years, and the mean body surface area affected was 19.3 +/- 16.2%. Mean duration of treatment was 14.3 +/- 9.6 months, number of session 113.5 +/- 88.6 times and cumulative dose 111.7 +/- 108.5 J/ cm2. Concomitant topical steroid was used in 88.9% patients. Repigmentation was moderate in 6 (40%) patients, good in 3 (20%), while 3 (20%) achieved excellent results. One patient (6.6%) showed no response and 2 (13.3%) showed poor repigmentation. Three patients developed side effects. NB-UVB phototherapy results in satisfactory repigmentation in our vitiligo patients and should be offered as a treatment option.

Independent component analysis for assessing therapeutic response in vitiligo skin disorder.

This paper describes an image analysis technique that objectively measures skin repigmentation for the assessment of therapeutic response in vitiligo treatments. Skin pigment disorders due to the abnormality of melanin production, such as vitiligo, cause irregular pale patches of skin. The therapeutic response to treatment is repigmentation of the skin. However the repigmentation process is very slow and is only observable after a few months of treatment. Currently, there is no objective method to assess the therapeutic response of skin pigment disorder treatment, particularly for vitiligo treatment. In this work, we apply principal component analysis followed by independent component analysis to represent digital skin images in terms of melanin and haemoglobin composition respectively. Vitiligo skin areas are identified as skin areas that lack melanin (non-melanin areas). Results obtained using the technique have been verified by dermatologists. Based on 20 patients, the proposed technique effectively monitored the progression of repigmentation over a shorter time period of six weeks and can thus be used to evaluate treatment efficacy objectively and more effectively.

Determination of skin repigmentation progression.

In this paper, we describe an image processing scheme to analyze and determine areas of skin that have undergone repigmentation in particular, during the treatment of vitiligo. In vitiligo cases, areas of skin become pale or white due to the lack of skin pigment called melanin. Vitiligo treatment causes skin repigmentation resulting in a normal skin color. However, it is difficult to determine and quantify the amount of repigmentation visually during treatment because the repigmentation progress is slow and moreover changes in skin color can only be discerned over a longer time frame typically 6 months. Here, we develop a digital image analysis scheme that can identify and determine vitiligo skin areas and repigmentation progression on a shorter time period. The technique is based on principal component analysis and independent component analysis which converts the RGB skin image into a skin image that represent skin areas due to melanin and haemoglobin only, followed by segmentation process. Vitiligo skin lesions are identified as skin areas that lack melanin (non-melanin areas). In the initial studies of 4 patients, the method has been able to quantify repigmentation in vitiligo lesion. Hence it is now possible to determine repigmentation progression objectively and treatment efficacy on a shorter time cycle.