Background: Some of the views contrasting the beneficial and toxic effects of antimicrobials upon wound healing remain controversial. Objective: To assess the clinical relevance of histological findings following antimicrobial applications on chronic leg ulcers. Method: The present study was performed in three parallel groups of 17 patients suffering from at least 2 similar chronic leg ulcers. Clinical planimetric assessments were performed before and after 3 and 6 weeks of treatment using hydrocolloid dressings. In addition, 1 ulcer in each patient received applications of povidone-iodine (PVP-I), silver sulfadiazine or chlorhexidine digluconate. Histological examinations were made at inclusion and after the 6-week therapy. Time to healing was also recorded. Results: At entry in the study, fibroblasts, macrophages, neutrophils and vessels were abundant in the ulcers. In addition, focal necrotizing vasculitis was related to the microbiological load. Compared to the control lesions, both the healing rate and time to healing of the leg ulcers showed a modest improvement at the sites receiving silver sulfadiazine (2–7%) or chlorhexidine digluconate (–1 to 5%). By contrast, PVP-I increased significantly the healing rate (4–18%, p < 0.01), and time to healing was reduced by 2–9 weeks (p < 0.01). The 3 antimicrobials decreased the bacterial density, and the vascular margination and migration of inflammatory cells, thus abating the vasculitic changes. PVP-I applications did not alter the microvessels and did not significantly reduce the density in dendrocytes and fibroblasts. By contrast, both silver sulfadiazine and chorhexidine digluconate appeared to alter the superficial microsvasculature including the dendrocyte population. Conclusion: Although topical antimicrobials may apparently achieve almost similar activity on the bacterial load inside chronic leg ulcers, the toxicity upon host cells was different among these agents. PVP-I appeared to be an efficient compound in these respects exhibiting a positive and relevant clinical effect.

Objective: To assess the effect of the position of a limb (dependency) on the cutaneous vasoconstrictor (blanching) assay (VCA) using topical corticosteroid preparations. Method: Two studies were performed on the forearms of healthy volunteers using tristimulus reflectance colorimetric assessments. The first one conducted in 60 normal adults aimed at quantifying the range of variation in the skin chromaticity a* when the arm was successively positioned horizontally and vertically, either in the upward or downward direction. In the second study, 16 volunteers were selected according to a weak spontaneous postural dependency of the limb in a* (<2 units). The blanching effect of 0.1% mometasone furoate, 0.1% betamethasone valerate and petrolatum were compared to the colour of an untreated site. Chromaticity a* and the colorimetric variable (ΔtL*² + Δta*²)^0.5 were measured in time following a 2-hour application. Results: The postural variations in skin colour varied among subjects. The majority of them (80%) presented a difference in a* higher than 2 units between the upright and downward arm positions. The upright position appeared to be the most sensitive to show significant differences in the VCA. Mometasone furoate exhibited the most prominent effect, significantly higher than betamethasone valerate and controls. Conclusion: The corticosteroid VCA is influenced by the position of the limb. The upright position increases the sensitivity of the test. Mometasone furoate is more potent than betamethasone valerate.