Central regions of keloids are severely ischaemic.

We classified scars as keloids, hypertrophic scars and mature scars, and then examined the scars for differences in central and marginal vascularization. We found significant differences in localized hypoxia-induced factor-1α (HIF-1α) expression and vascular density in keloids, but no localized differences in hypertrophic or mature scars. The central areas of keloids exhibited higher HIF-1α expression and lower vascular density than marginal areas, suggesting that the former are severely ischaemic.