A “pock” refers to a skin lesion resulting from an infectious disease, typically characterized by the formation of pustules. These marks are a form of atrophic scarring, meaning they are depressed or sunken into the skin’s surface. Historically, these permanent indentations were a common sign of having survived certain widespread viral illnesses.
Defining the Pockmark
A true pockmark is the depressed scar left after a severe inflammatory skin lesion damages the underlying tissue. The process begins with a papule that progresses into a vesicle, which then fills with pus to become a pustule. This pustule extends deep into the dermis, causing significant tissue destruction.
When the body attempts to repair this deep wound, it fails to produce sufficient collagen to replace the lost dermal tissue. This deficit leaves a concave indentation in the skin, which is the defining characteristic of an atrophic scar. Dermatologically, these scars are often classified as ice pick, boxcar, or rolling scars, depending on their depth and shape. The visible pitting occurs because the base of the healed lesion is anchored to the deeper subcutaneous tissue, pulling the surface skin inward.
Diseases Associated with Pock Formation
The term “pock” is most associated with smallpox, caused by the Variola virus. Smallpox lesions were notorious for penetrating the dermis deeply, leaving behind severe and widespread pockmarks on the face and body of up to 65% of survivors. This disease was the historical source of the term.
Other viral infections can also lead to pock-like scarring, though with less severity. Chickenpox, caused by the Varicella-zoster virus, produces blisters that can result in atrophic scars, particularly if the lesions are scratched or become secondarily infected with bacteria. Cowpox is another related Orthopoxvirus that can cause localized lesions, but its scarring potential is far less significant than smallpox.
Pockmarks in the Modern Era
Due to global vaccination efforts, the World Health Organization certified the eradication of smallpox in 1980. Consequently, the distinct pockmarks caused by Variola are now extremely rare among living populations. The term “pockmark” has since broadened to describe any deep, pitted, or atrophic scar, regardless of the original cause.
Today, the most common cause of pock-like scarring is severe inflammatory acne, which creates damage in the dermis similar to that of a viral pustule. Modern dermatology focuses on treating these generalized atrophic scars using methods that stimulate new collagen production. Treatments include microneedling, which creates controlled micro-injuries, and laser resurfacing, which ablates damaged skin layers to encourage regeneration. Injectable dermal fillers are also used to manually raise the depressed scar tissue.