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.

Clinical study on syphilis in Abu Dhabi with special stress on the unusual presentation of the disease.

Seventy-nine cases of syphilis were the material of this study. Unusual presentations of primary syphilis were found in 42.5% of cases; explanations are given for these findings. Other aspects of the unusual presentations of the disease were studied with special stress on the occurrence of itching in the course of secondary syphilis. The authors emphasize that pruritus as a presenting symptom in the presence of skin lesion suggestive of syphilis should not blind the physician to the possibility that Treponema pallidum may be the etiologic agent.

Distribution of Blood Groups Among Syphilitic Abu Dhabians in the United Arab Emirates.

ABO and Rh blood groups among 54 syphilitics were determined. A significantly increased incidence of syphilis in persons blood groups B and AB was observed; significant decrease in those having groups A and 0. A significant decrease in, the incidence of syphilis was also observed in Rh negative 'subjects. These results suggest a possible relationship between the inheritance of blood groups and the natural defence mechanism against syphilis.

Behçet's disease: clinical study of Jordanian patients.

BACKGROUND: Behçet's disease is a chronic, recurrent, inflammatory disorder characterized by the triad of oral and genital ulcers and ocular lesions. The etiology is unknown. This is the first report giving details of the clinical manifestations of Behçet's disease in Jordanian patients. METHODS: Twenty patients with Behçet's disease were studied to determine the clinical pattern in the North of Jordan. The patients were seen in Princess Basma Teaching Hospital in North Jordan. They presented to various clinics and underwent full clinical examination. Data for each patient on all features of Behçet's disease were recorded on a standard form. A comparison was made between Behçet's disease in Jordan and other countries in the region. RESULTS: Of the 20 patients, 14 were men and six women, giving a ratio of 2.3:1. Their ages ranged from 14 to 58 years. All had mouth ulcers, 65% genital ulcers, 65% ocular involvement, 55% joint involvement, 35% skin lesions, 20% vascular lesions, and 5% gastrointestinal involvement. The oral ulcers were the first manifestation of the disease process in 70% of our patients. Skin lesions, genital ulcers, and involvement of the central nervous system and the pulmonary system were less frequent in our study. CONCLUSIONS: Although it is difficult to obtain figures as to the incidence and prevalence of Behçet's disease in Jordan, the clinical manifestations, with a few exceptions, are similar to those in other countries in the region.