Differences between first and second pain
First and second pain refers to the immediate and delayed pain responses to noxious stimulation. Other terms that denote these pains are fast and slow pain or sharp/pricking and dull/burning pain.
The stimuli that generate first pain are transmitted by A delta, small, myelinated afferents. Second pain results from activation of C fibers, which conduct impulses much more slowly, thus accounting for the time difference.