Scar tissue is often more sensitive than normal skin primarily because it contains a higher density of pain receptors compared to the original tissue it replaced.
Here's a more detailed explanation:
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Increased Pain Receptors: When the body repairs itself after an injury, the new tissue (scar tissue) frequently develops with a denser network of nociceptors. Nociceptors are sensory receptors that detect pain signals. This abundance of pain receptors can make the area more sensitive to stimuli that wouldn't normally cause pain in healthy tissue.
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Nerve Entrapment and Hypersensitivity: Scar tissue can sometimes entrap or compress nearby nerves. This compression can lead to nerve irritation and increased sensitivity in the affected area. Even light touch can trigger pain signals.
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Lack of Specialization: Unlike normal skin, scar tissue lacks specialized structures like hair follicles and sweat glands. This lack of complex structures impacts the normal sensation and sensitivity, often resulting in an amplified pain response.
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Collagen Fiber Alignment: The collagen fibers in scar tissue are aligned differently than in normal skin. They tend to be arranged in a less organized, parallel fashion. This altered structure can contribute to the altered sensory perception, including heightened sensitivity.
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Proprioception Alterations: Scars can sometimes impact proprioception, which is the body's sense of its position and movement. Altered proprioception can contribute to feelings of discomfort and increased sensitivity in the area surrounding the scar.
While the reference provided also mentions scar tissue being "weak" and prone to re-injury, this is a separate issue from its sensitivity. While related (re-injury would stimulate pain receptors), the direct cause of the heightened sensitivity is the increased number of pain receptors and potential nerve entrapment. The contraction of scar tissue during sleep can also exacerbate the perception of pain and sensitivity.
In summary, the increased sensitivity of scar tissue is mainly due to the amplified presence of pain receptors in the affected area, potential nerve compression within the scar, and alterations in the tissue's structure and nerve function.
