Spectroscopic assessment of dermal melanin using blue vitiligo as an in vivo model Iltefat Hamzavi 1, n , Natalie Shiff 1 , Magda Martinka 1 , Zhiwei Huang 1 , David McLean 1 , Haishan Zeng 1,2 , Harvey Lui 1,2 1 Division of Dermatology, University of British Columbia and Vancouver General Hospital 2 Cancer Imaging Department, British Columbia Cancer Agency Background: Spectroscopic methods have been used to analyze in vivo melanin in the past but the specific effect of melanin depth on autofluorescence and reflec- tance spectroscopy has not been determined. In patients with blue vitiligo, three distinctive clinico- pathologic patterns are present: (1) normal skin with normal epidermal melanin pigmentation (2), skin of blue vitiligo with dermal melanin pigmentation, and (3) tissue of regular vitiligo with no melanin pigmentation. Blue vitiligo may thus serve as an in vivo model to assess dermal pigment using spectroscopic techniques. Objectives: To evaluate the reflectance and auto- fluorescence spectra of a patient with blue vitiligo in order to assess the effect of melanin pigmentation and its localization on the optical properties of the skin. Methods: The blue-gray, normal and depigmented lesions of a patient with blue vitiligo were analyzed using reflectance and fluorescent spectroscopy. The condition was likely induced by a phototoxic reaction in a patient with pre-existing vitiligo. These data were then correlated to the histologic and electron microscopic findings present in the various types of lesions. Results: Reflectance spectroscopy detected little dif- ference in spectral shape between skin sites affected by blue vitiligo vs. vitiligo. Autofluorescence spectroscopy detected an apparent difference between the two types of lesions, with the blue–gray lesions (blue vitiligo) showing lower fluorescence intensity and spectral max- imum position red-shifted compared with regular viti- ligo, whereas regular vitilgo showed more intense hemoglobin absorption than the blue vitiligo. Conclusions: Dermal melanin present in blue vitiligo can be well characterized by autofluorescence spectro- scopy, while little difference in reflectance spectral shape exists between vitiligo and blue vitiligo. Thus, autofluorescence spectroscopy may better identify dee- per structures in skin tissue, such as melanin, than reflectance spectroscopy Key words: 5-amino salicylic acid; blue vitiligo; dermal melanin; melanin; mesalazine; phototoxicity; spectro- scopy. V itiligo is a common condition defined by the development of depigmented white macules and patches that histopathologically demonstrate an ab- sence of melanocytes in the epidermis (1). Trichrome vitiligo and blue vitiligo are two distinct clinical variants of this condition. Trichrome vitiligo is char- acterized by the presence of hypopigmented areas that are intermediate in color to normal skin and typical vitiligo (2). Histologically, these intermediately pig- mented areas contain a few dermal melanophages and a decreased number of epidermal melanocytes (2). In blue vitiligo, the affected skin appears blue gray (3), and corresponds histologically with an absence of epidermal melanocytes and numerous dermal mela- nophages. A previously published case report of blue vitiligo occurred in an HIV-positive patient with vitiligo, who developed dermatitis after psoralens and ultraviolet A radiation (PUVA) phototherapy while on zidovudine and bleomycin. The blue lesions were felt to be secondary to postinflammatory hyper- pigmentation either owing to PUVA or the patient’s HIV medications (3). According to Klienle et al. (4), the blue appearance of veins in the skin is due to four factors: (1) the differential scattering and absorption characteristics n Present address: Henry Ford, Health System and Clinical Assis- tant Professor of Dermatology, Department of Dermatology, Wayne State University, Detroit, MI, USA. Photodermatol Photoimmunol Photomed 2006; 22: 46–51 Blackwell Munksgaard r 2006 The Authors. Journal compilation r 2006 Blackwell Munksgaard 46