Pockmarks are permanent depressions or indentations in the skin’s surface resulting from damage. These concave blemishes are structurally different from the surrounding skin and are collectively known as atrophic scars. While the term historically referred to the lasting marks of smallpox, modern pockmarks are primarily a consequence of severe inflammatory conditions. Understanding how these scars form and the specific types that exist is the first step toward exploring advanced treatments to smooth the skin’s texture.
Defining Pockmarks and Their Causes
Pockmarks are a subtype of atrophic scars, characterized by a sunken appearance below the level of the surrounding skin. This depression occurs when the normal healing process is disrupted, leading to an insufficient amount of supportive tissue. The most frequent modern cause of these scars is severe, inflammatory acne, specifically cystic acne, which affects the deeper layers of the skin.
Nearly 95% of individuals who experience acne may develop some form of scarring, with atrophic scars being the most common type. Other conditions, such as the viral infection varicella (chickenpox), can also cause pockmarks when fluid-filled blisters damage the skin’s deeper layers. Historically, the term was associated with smallpox, but current clinical focus is almost entirely on post-inflammatory conditions like acne and trauma.
The Biology of Scar Formation
The depressed appearance of pockmarks stems from an imbalance in the body’s wound-healing response, resulting in a net loss of dermal tissue. This process begins with deep inflammation, where immune cells release enzymes that degrade the structural proteins of the dermis. This enzymatic activity breaks down collagen and elastin fibers, which provide the skin with its strength and elasticity.
During the repair phase, the body fails to regenerate enough new collagen to fill the void created by tissue destruction. This deficiency in structural support causes the affected area to collapse inward, forming the indentation. In some scar types, fibrous bands of tissue form beneath the scar, anchoring the epidermis to deeper subcutaneous structures. This tethering effect physically pulls the skin surface down, intensifying the characteristic sunken look.
Classifying Atrophic Scars
Dermatologists classify atrophic scars into three types based on their morphology, which guides the most effective treatment approach. Icepick scars are the first category; they are narrow, deep, and V-shaped, often resembling a puncture wound. These scars extend down into the dermis, sometimes reaching the subcutaneous fat, and represent 60% to 70% of all atrophic scars.
Boxcar scars are wider, U-shaped depressions with sharp, clearly defined vertical edges. These scars vary in depth, but their base is relatively flat and parallel to the skin’s surface, giving them a box-like appearance. Boxcar scars often resemble the marks left by chickenpox and commonly appear on the cheeks and temples.
The third type is rolling scars, which are broad, shallow depressions with sloping, ill-defined edges, creating a wave-like or uneven texture. They are caused by the destruction of underlying fat and the tethering of the dermis to the subcutaneous tissue. Because of this fibrous anchoring, rolling scars become more noticeable when the skin ages and loses elasticity.
Modern Treatments for Scar Reduction
Treatment for atrophic scars is individualized, often requiring a combination of procedures to address the unique characteristics of each scar type. Laser resurfacing utilizes focused light to either remove the outer layer of skin (ablative lasers like CO2 or Er:YAG) or stimulate collagen production beneath the surface (non-ablative lasers). Ablative lasers physically remove scar tissue to promote smoother healing, while non-ablative lasers, such as Nd:YAG, tighten skin and stimulate collagen with minimal downtime.
Subcision is a minor surgical technique effective for rolling scars, which are defined by fibrous tethers. This procedure involves inserting a needle beneath the scar to mechanically break the tissue bands that pull the skin downward, allowing the scar to rise. Following subcision, dermal fillers (often hyaluronic acid-based) can be injected to immediately lift the depressed area and provide a scaffold for new collagen growth.
For icepick scars, which are too deep for simple resurfacing, the Chemical Reconstruction of Skin Scars (CROSS) technique is used. This involves the focal, high-concentration application of a chemical agent, like trichloroacetic acid (TCA), directly into the scar to induce controlled injury and collagen synthesis. Microneedling, especially when combined with radiofrequency (RF) energy, creates controlled micro-injuries to stimulate new collagen and elastin, helping to remodel and smooth the texture of boxcar and rolling scars.