An atrophic scar is a specific type of scar characterized by a depression, pit, or indentation in the skin’s surface. The term “atrophic” refers to a lack of tissue volume, causing these scars to appear sunken below the level of the surrounding healthy skin. This sunken appearance distinguishes them from raised scars, such as hypertrophic scars or keloids, which result from an excess of tissue production.
Identifying the Appearance and Common Causes
Atrophic scars are visually distinct due to their sunken or pitted appearance, which varies widely in shape and depth. These indentations often give the skin a noticeable uneven texture, sometimes described as crater-like or wavy. The scar tissue is typically thinner and more fragile than the adjacent skin due to the underlying structural deficit. While the color may initially be red or dark, mature scar tissue often appears lighter than the surrounding skin.
These scars form following an inflammatory event or injury that causes significant damage to the skin’s deeper layers. The most frequent cause is severe, inflammatory acne, particularly cystic acne, where deep lesions destroy underlying tissue. Other common triggers include viral infections like chickenpox, which cause lesions that penetrate the dermis. Traumatic injuries or surgical procedures can also result in an atrophic scar if the wound healing process is compromised.
The Biological Mechanism of Tissue Loss
The indentation of an atrophic scar results from a failure to adequately replace lost tissue during the healing process. When the skin is deeply injured, the body initiates a repair mechanism involving the production of new connective tissue. This process fails due to insufficient synthesis of structural proteins, specifically collagen and elastin fibers, within the dermis. This underlying deficit, known as dermal atrophy, causes the surface layer of the skin to collapse into the void.
The initial inflammatory phase of the injury plays a significant role in this outcome. Heightened inflammation, such as that seen in cystic acne, leads to the excessive release of enzymes called matrix metalloproteinases (MMPs). These MMPs actively degrade the collagen and elastin that form the skin’s supportive extracellular matrix. If this degradation outpaces the body’s ability to synthesize new tissue, the skin’s structural integrity is compromised, causing the overlying tissue to sink.
Classifying Atrophic Scar Types
Atrophic scars are categorized into three main morphological types, which helps determine the most effective treatment approach. Ice Pick Scars are the narrowest and deepest, appearing as sharp, V-shaped pits that resemble a puncture mark. They often extend deep into the dermis, making them challenging to treat effectively with superficial methods. These scars are typically less than two millimeters wide at the skin’s surface.
Boxcar Scars are wider than ice pick scars and have sharply defined, vertical edges, giving them a box-like or crater appearance. The base of the scar is relatively flat, and while depth varies, their well-demarcated borders distinguish them from other types. They commonly result from widespread inflammatory lesions and are frequently found on the temples and cheeks.
Rolling Scars are characterized by a broad, undulating depression with sloping, ill-defined edges, giving the skin a wavy, uneven texture. These scars form when fibrous bands of tissue develop between the dermis and the subcutaneous fat below. These bands pull the overlying skin downward, creating widespread surface contour irregularities.
Clinical Approaches to Scar Revision
Treating atrophic scars focuses on elevating the depressed tissue and stimulating the production of new collagen to rebuild the dermal structure. Volume Restoration techniques, like the injection of dermal fillers, are often used to physically raise the base of rolling and some boxcar scars. These temporary fillers, typically composed of hyaluronic acid, provide immediate volume beneath the scar and can sometimes be combined with other treatments.
For scars that are tethered, a minor surgical procedure called Subcision is often utilized to release the fibrous bands that pull the skin down. A specialized needle is inserted under the scar to manually break the underlying attachments, allowing the skin to lift and prompting a healing response that includes new collagen formation. This method is particularly effective for treating rolling scars.
Resurfacing procedures aim to remove damaged surface layers and stimulate repair. Ablative laser therapy and deep chemical peels work by creating controlled injury to the skin, triggering a healing cascade to produce smoother, new tissue. For widespread texture improvement, Collagen Induction therapies like microneedling, sometimes enhanced with radiofrequency energy, create micro-injuries. These micro-injuries stimulate the body’s natural collagen production deep within the dermis.