Elizabeth Martin and Robert Hine. Latest Edition (7 ed.) Fully revised and updated, the sixth edition of this dictionary provides comprehensive coverage of biology, biophysics, and biochemistry, as well as key terms from medicine and palaeontology.
For example, if someone scratches a mole until it bleeds, the resulting lesion, a crust, is now a secondary skin lesion. The most common secondary skin lesions include: 1  crust: a crust, or a scab, is created when dried blood forms over a scratched and irritated skin lesion. 2  ulcer: typically caused by a bacterial infection or physical trauma. 3  scale: patches of skin cells that build up and then fall off the skin.
Best Answer: Actually, scabs don't itch. Scabs are just crusts of dried blood and fiber that cover a wound. It is the wound that itches. In the healing process, some of the nerve fibers that mediate both pain and itch become irritated and inflamed. This process leads to the itch we encounter. This itch is actually a small pain.