Which sensitization can only cause sensitization to heat?

• A. Thermal desensitization
• B. Peripheral sensitization
• C. Central sensitization
• D. Mechanical sensitization

Answer: (B)

Peripheral sensitization happens when peripheral nociceptors become more excitable after tissue injury or inflammation. Inflammatory mediators like prostaglandins, bradykinin, and NGF lower the activation thresholds of these fibers, especially the heat-sensitive ones (such as TRPV1 on heat-pain fibers). That makes heat signals easier to evoke, producing thermal hyperalgesia. Central sensitization, by contrast, is about increased responsiveness of spinal or brain circuits and tends to amplify pain across multiple modalities, not just heat. Mechanical sensitization refers to heightened sensitivity to mechanical stimuli (pressure, touch). Thermal desensitization would reduce heat sensitivity rather than increase it. So the sensitization that can specifically manifest as increased heat sensitivity is peripheral sensitization.