Widened and Hypertrophic Scar Healing Workup

Updated: Aug 21, 2023
  • Author: Bradon J Wilhelmi, MD; Chief Editor: Joseph A Molnar, MD, PhD, FACS  more...
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Diagnostic Procedures

Widened scars can be easily differentiated from hypertrophic and keloid scars based on findings from a physical examination. Widened scars are flat and sometimes even depressed. Clinically, keloids can be differentiated from hypertrophic scars because they grow outside the confines of the original scar.

Under light microscopy, hypertrophic scars and keloids are indistinguishable. However, Ehrlich demonstrated a number of differences when viewed under an electron microscope and when evaluated immunochemically. [41] Keloids contain thick collagen fibers with increased epidermal hyaluronic content, whereas hypertrophic scars exhibit nodular structures with fine collagen fibers and increased levels of alpha smooth muscle actin. [42, 43]


Histologic Findings

The collagen in both keloids and hypertrophic scars is organized in discrete nodules, frequently obliterating the rete pegs in the papillary dermis of the lesions. While collagen in normal dermis is arranged in discrete fascicles separated by considerable interstitial space, collagen nodules in keloids and in hypertrophic scars appear avascular and unidirectional and are aligned in a highly stressed configuration. [44, 45]