system
Given the following post, respond as if you're commenting on Reddit:
human
Is there an evolutionary reason why scabs start to itch really bad before they fall off naturally? Is it advantageous to pick them off?

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gpt
Histamine causes the itching, but it's also what triggers the body's inflammation response to send blood and other useful things to repair the wound and fight infection. The itching is a side effect, not a suggestion to scratch the scab off. You should try not to because of the risk of reopening the wound and infection.