Which statement best defines primary hyperalgesia?

Which statement best defines primary hyperalgesia?

• A. Sensitization of surrounding nociceptors after injury or inflammation.
• B. Sensitization of dorsal horn cells after injury.
• C. Increased pain threshold.
• D. Reduced nociceptor sensitivity.

Answer: (A)

Primary hyperalgesia comes from peripheral sensitization at the injury site. When tissue is damaged, inflammatory mediators release locally and make nearby nociceptors more excitable, lowering their activation threshold. As a result, the same stimulus feels more painful because the peripheral nerves at the injured area respond more strongly. This is different from central sensitization, which involves the spinal cord and leads to heightened pain in surrounding areas (secondary hyperalgesia) and can cause allodynia. So the best description is sensitization of peripheral nociceptors after injury or inflammation.

Primary hyperalgesia comes from peripheral sensitization at the injury site. When tissue is damaged, inflammatory mediators release locally and make nearby nociceptors more excitable, lowering their activation threshold. As a result, the same stimulus feels more painful because the peripheral nerves at the injured area respond more strongly. This is different from central sensitization, which involves the spinal cord and leads to heightened pain in surrounding areas (secondary hyperalgesia) and can cause allodynia. So the best description is sensitization of peripheral nociceptors after injury or inflammation.