Acne scarring is a common dermatological concern that follows the resolution of inflammatory acne vulgaris. These scars are permanent changes in skin texture that occur when the body’s natural healing process is disrupted after a severe breakout. The most prevalent type is the atrophic scar, which affects 80 to 90 percent of patients who develop scarring. Atrophic scars are characterized by depressions, indentations, or pits in the skin surface, indicating a net loss of underlying tissue structure due to damage in the deep layers of the skin during the inflammatory phase.
How Atrophic Scars Form
The formation of atrophic scars is rooted in the body’s response to intense inflammation. When a severe acne lesion, such as a nodule or cyst, develops deep within the dermis, it triggers a prolonged and aggressive immune response. This sustained inflammatory state involves the release of enzymes that break down the skin’s structural proteins, specifically collagen and elastin fibers. While the skin attempts to heal the damage, there is insufficient production of new collagen to rebuild the dermal framework effectively. This inadequate repair process results in a tissue deficit, causing the overlying skin to sink and form a depression.
The Three Main Types of Atrophic Scars
Atrophic scars are categorized into three distinct morphological types, each reflecting a different pattern of tissue damage and shape. Accurate identification of the specific scar type is important, as it dictates the most appropriate treatment strategy. Individuals often present with a combination of these scar types.
Icepick Scars
Icepick scars are the most common atrophic scar type, representing 60 to 70 percent of all atrophic lesions. They are narrow, deep, V-shaped pits that extend vertically into the dermis, resembling a puncture mark. These scars are typically less than 2 millimeters wide and are deeper than they are wide, forming a steep, sharp-edged pit. Their depth makes them challenging to treat with traditional skin resurfacing methods that target only the superficial layers.
Boxcar Scars
Boxcar scars are characterized by their round or oval shape and sharply defined, vertical edges, giving them a box-like appearance. These depressions are wider than icepick scars, generally measuring between 1.5 and 4 millimeters across. Boxcar scars can be either shallow, with a depth of less than 0.5 millimeters, or deep, exceeding 0.5 millimeters. The distinct, vertical walls of these scars do not slope, which helps differentiate them from the third type of atrophic scar.
Rolling Scars
Rolling scars are broad, saucer-shaped depressions with gently sloping edges, lending the skin an undulating or wavy appearance. These scars are usually the widest, often measuring 4 to 5 millimeters or more. Rolling scars are caused by fibrous bands of tissue tethering the dermis to the deeper subcutaneous layer. These bands pull the skin surface down, creating the characteristic “rolling” appearance that is more noticeable in certain lighting.
Professional Treatment Approaches
Since atrophic scars involve a structural loss of tissue, professional in-office procedures are needed to elevate the depressions and smooth the skin texture. Treatment plans are often multi-modal, combining several techniques tailored to the specific types and depths of scars. The goal of these procedures is to either physically release the scar or to stimulate significant new collagen production.
Subcision
Subcision is a technique effective for treating rolling scars and some broad boxcar scars. This procedure involves inserting a fine needle or cannula beneath the scar to mechanically break the fibrous strands that are tethering the skin down to the subcutaneous tissue. The process creates a controlled wound, which upon healing, releases the depression and stimulates the formation of new collagen and elastic fibers.
Dermal Fillers
For broader and shallower boxcar and rolling scars, dermal fillers offer an immediate volume-replacing solution. Injectable products, such as hyaluronic acid-based fillers, are placed directly beneath the scar to physically raise the depressed area to the level of the surrounding skin. While hyaluronic acid fillers are temporary, semi-permanent options are available for a longer-lasting correction.
Laser Resurfacing
Laser resurfacing uses focused light energy to remodel scar tissue and is classified into ablative and non-ablative types. Ablative lasers, such as Carbon Dioxide (CO2) and Erbium YAG, vaporize the outer layers of damaged skin. This leads to significant skin tightening and new collagen synthesis, making them effective for deep boxcar scars. Non-ablative lasers heat the deeper dermal layers without removing the surface skin, stimulating collagen production beneath the epidermis for general texture improvement.
TCA CROSS
The chemical reconstruction of skin scars, or TCA CROSS technique, is highly effective for deep, narrow icepick scars. This procedure involves the focal application of a high concentration of Trichloroacetic Acid (70 to 100 percent) directly to the scar base using a fine applicator. This application induces a controlled, localized chemical burn that triggers an intense inflammatory reaction deep within the scar. The subsequent healing process generates robust collagen production, which works to raise the floor of the icepick scar.
Microneedling
Microneedling, also known as percutaneous collagen induction therapy, uses a device to create thousands of micro-punctures in the skin. This controlled injury initiates a cascade of wound-healing growth factors, leading to widespread collagen and elastin synthesis across the treated area. This technique can be enhanced by combining it with Platelet-Rich Plasma (PRP), an autologous blood product rich in growth factors that further promote tissue repair.