There is nothing that you can't scratch if you really want to. You just need to do it carefully so as not to damage the tissue, especially when healing a wound. The granulations are very delicate. You can simply stroke or anoint it with ointment so that it does not dry out.
And they itch because they dry out and the nerve endings react, as they are superficial.
Itching is not what cannot be scratched, but what cannot be scratched - itches. :)
Unbearable itching that occurs at a certain stage of treatment is a signal of wound healing.
A healing wound itches for several reasons.
Any wound is inflammation ... The human body itself struggles with the consequences of the injury: processes of rejection of damaged tissue, wound cleansing, and the formation of new cells take place in the wound. The duration of these processes and our well-being depends on the types of wounds. The consequences of healing wounds also depend on this.
During wound healing (at the last stage of inflammation - in the regeneration phase), inflammatory mediators are released. Histamine is one of them. First of all, histamine is the main reason for itching.
Therefore, it is the healing wound that itches, because in the fourth phase of inflammation, the production of histamine is maximal. The reaction of the body and wounds, in particular, to the production of histamine is allergy. An excess of it leads to a sensation of severe itching. But with the direct participation of histamine, new cells are formed, due to which the edges of the wound are tightened, and its tissues are restored. After the wound has healed, histamine levels return to normal.
Itching is a perverse pain response. Pain is the body's defense response. And pain is an indicator of a place that something is going wrong somewhere. In the case of chickenpox, there is an infectious lesion that manifests itself on the skin with certain elements. This is a kind of inflammation. A mosquito bite is an allergic reaction to a protein in the saliva of an insect. And with abrasions, inflammation also appears - whole teams of cells work alone to neutralize microbes that could get into the wound, others for its further healing, etc. This is the cause of the itching.
Most often, this cannot be done in the modern world for a modern person with modern hygiene products. We also itch when we haven't bathed for a long time. For millions of years, all humanity has not had a soul.
Moreover, other animals are scratching to disperse and disturb the animals that have started up on the body. And the refrex could simply be inherited and serve a person with a similar purpose. Yet throughout the history of mankind, people could wash infrequently, irregularly, and not as efficiently as they are now - plunge into the river and scratch themselves in the water or in the rain.
Itching can be physiological and pathological. When something that should not be scratched (insect bites, etc.) itches, this is a sign that histamine, a mediator of allergic reactions, is being released. It causes an irresistible urge to scratch.
Any inflammation initiates the production of inflammatory mediators - serotonin, histamine, acetylcholine, norepinephrine, etc. These mediators can irritate skin receptors, the omnipotence of which there is an itching sensation. Also, swelling at the site of inflammation contributes to the compression of receptors and their irritation.