Lots of theories have been put forth as why a healing wound gives an itching sensation. There has been lots of speculation on this subject even for medical professionals.
During the healing process, the skin undergoes many changes. As a part of healing, our body releases may factors until the growth of new skin on the affected area of the skin is complete. It could be because of this reaction of our body, itching sensation is created and when the skin is back to its normal state, the itch stops.
One such chemical released during the healing process is the histamine. This substance is generally produced by the body when an allergen or foreign particle enters the body. The histamine normally causes what are called ‘allergic’ reactions like itching, swelling, rashes etc over the parts of body. So, histamine production could be one reason for the itching sensation on a healing wound.
Yet another reason is formation of new skin. We know that dry skin normally itches. A hard covering of dried blood that forms on the affected part of the skin over the wound as a part of healing process is called scab. Scabs are dry and rough. During the development of new skin, these scabs might stimulate itching sensation. Also during this stage, collagen is being released to create new skin that stretches across the wound. New skin is normally more sensitive. This leads to more itching sensations.