An in vivo model of postinflammatory hyperpigmentation and erythema: clinical, colorimetric and molecular characteristics.

BACKGROUND: Postinflammatory hyperpigmentation (PIH) is a common, acquired pigmentary disorder of the skin associated with significant quality-of-life impairment, especially in individuals with skin of colour. Current treatment for PIH is limited, largely due to a poor understanding of disease pathogenesis and the lack of a representative disease model. OBJECTIVES: This study is intended to further develop, update and validate our previously designed in vivo model of acne-induced PIH/postinflammatory erythema (PIE) using different concentrations of trichloroacetic acid (TCA), a medium-depth chemical peel. METHODS: Twenty-nine patients with skin types II-VI and clinician-confirmed presence of two or more truncal acne pustules and PIH/PIE were included. On the basis of Investigator's Global Assessment (IGA), clinical polarized photography (CPP), colorimetry and Skindex, we experimentally determined an optimum TCA concentration and assessed our model's ability to exhibit a dose-response relationship between degree of inciting insult and severity of resulting pigmentation. We also performed differential microRNA profiling and pathway analysis to explore the potential of microRNAs as molecular adjuncts to our model. RESULTS: Application of TCA 30% produced lesions indistinguishable from acne-induced PIH and PIE lesions on the basis of colorimetry data without causing epidermal necrosis. Application of progressively increasing TCA doses from 20% to 30% resulted in concentration-dependent increases in CPP, IGA and colorimetry scores at all timepoints during the study. miRNA-31 and miRNA-23b may play a role in PIH pathogenesis, although further validation is required. CONCLUSIONS: Our TCA-based in vivo model, using TCA concentrations between 20% and 30% with an optimum of 30%, enables the quantitative assessment of the pigmentary response to varying degrees of cutaneous inflammation in a fashion that mirrors natural acne-induced PIH and PIE.

An in vivo model for postinflammatory hyperpigmentation: an analysis of histological, spectroscopic, colorimetric and clinical traits.

BACKGROUND: Acne vulgaris is a common condition that occurs in all skin types. Postinflammatory hyperpigmentation (PIH) is often associated with acne in patients of darker skin types, making it a common complaint in dermatology offices. Despite this, there is limited understanding of and effective treatment options for PIH. OBJECTIVES: The study objective was to validate an in vivo model for PIH and to compare the clinical, histological and spectroscopic characteristics of artificially induced PIH and acne-induced PIH. METHODS: A nonblinded, nonrandomized pilot study was performed. Thirty subjects served as their own control in which four sites treated with 35% trichloroacetic acid (TCA) solution and four truncal acne pustules were followed for 8 weeks and were evaluated clinically and histologically, and by colorimetry and spectroscopy. RESULTS: The initial phases of inflammation between TCA- and acne-induced PIH differ. However, clinical evaluations were similar on and after day 14. Acne- and TCA-induced lesions were clinically, histologically and spectroscopically indistinguishable at day 28. CONCLUSIONS: Clinical, spectroscopic and histological similarities of acne-induced and TCA-induced PIH at day 28 suggest that TCA-induced PIH can be a reproducible model for the study of acne-induced PIH.

Surgical interventions for vitiligo: an evidence-based review.

BACKGROUND: Vitiligo is a disfiguring disease, characterized frequently by the presence of de-pigmented macules and/or patches. Traditional therapies are essentially medical and are most preferred by dermatologists. Surgical therapies, however, are amongst the most effective interventions for vitiligo but are limited by their invasive nature, as well as the training and expertise needed to perform specific procedures. OBJECTIVES: To assess the evidence for the effectiveness, safety and applicability of the various surgical methods in the treatment of vitiligo. METHODS: For this systematic review of vitiligo surgical therapies, our searches included: PubMed, MEDLINE and Cochrane databases. RESULTS: We reviewed research studies reporting on split thickness skin grafts (STSG), punch/mini-graft, blister roof grafting, cultured and non-cultured cellular transplantation (MKTP). While all methods vary in their repigmentation outcomes, STSG is found to have the highest repigmentation success rate. Overall, post-operative complications included milia, scarring, cobblestone appearance or hyperpigmentation of treated areas. CONCLUSION: This review highlights the need for more randomized controlled trials in this field, underpinned by a more standardized objective approach to the assessment of repigmentation following surgical interventions.