Why does removing chickenpox scabs before they heal leave a scar, while removing normal scabs does not?
• Healthy scabs can in fact leave inconspicuous scars, but the more you scratch them, the worse the scar will become. Healing clean wounds starts with a growth of scaffolding tissue to contain the damage. Next the scar tissue begins adjusting its structure to its functions. In small, clean lesions of simple shape, the scar tissue may adapt so neatly that one hardly notices the mark that is left behind. However, scaffolding tissue cannot form so neatly on larger wounds, so they leave more conspicuous scars that may take years to shrink or may require plastic surgery. Interfering with scar formation, by repeatedly scratching a scab, for instance, aggravates scarring. Also, when the tissues are infected with germs such as chickenpox virus, the pathogens not only interfere with tissue growth, they attract the leucocytes that can form pus. Left alone, healthy leucocytes cleanly kill both the pathogens and infected tissue; they cordon off the pustule till everything dries and sloughs off, so
