Britannica
Sources used in this answer
Why did smallpox scars remain after the pustules healed?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
smallpox
Edward Jenner vaccinating his child against smallpox; colored engraving.
Smallpox scars occurred because the disease caused a severe rash that progressed from flat spots to raised papules, then to fluid-filled vesicles, and finally into infected pustules. These pustules were filled with pus, which consists of a mixture of necrotic inflammatory cells.12
In nonfatal cases, these pustules eventually dried up to form scabs. When these scabs separated from the skin, they left behind the characteristic pockmarked scars. The scarring was a result of the deep tissue involvement and the inflammatory response associated with the pustular stage of the disease.12