Acne affects many individuals, and resulting scars often persist long after breakouts resolve. Scars that appear as depressions are known as atrophic scars, forming due to a net loss of tissue during healing. Understanding the specific type of atrophic scar is the initial step toward finding the most effective treatment plan.
Understanding Boxcar Scars
Boxcar scars are a common subtype of atrophic acne scarring, characterized by broad, round or oval depressions with sharply defined vertical edges. They often resemble small, punched-out craters in the skin. These scars form when intense inflammatory acne, such as cystic lesions, causes localized destruction of collagen fibers and underlying fatty tissue within the dermis. When the skin attempts to repair the damage, insufficient new collagen is produced to fill the void, leading to a fixed depression. Boxcar scars differ structurally from icepick scars, which are much narrower and deeper.
The Permanence of Boxcar Scars
Boxcar scars are considered permanent without professional intervention. The depressed nature of the scar results from a structural deficit—the physical loss of dermal collagen and elastin. This missing foundational tissue cannot be spontaneously regenerated by the body. While the redness associated with a new scar will fade over many months, the indentation itself remains fixed. Treatment must physically rebuild or restructure the deep dermal layer to raise the base of the scar.
Non-Invasive and Topical Approaches
Non-invasive methods and topical products offer only minor improvement for established boxcar scars, but they support overall skin texture and tone. Topical retinoids, such as Tretinoin or Retinol, accelerate skin cell turnover and promote new collagen production over time. Consistent, long-term use can subtly soften the appearance of very shallow scars but cannot fully correct the depth of a structural depression. Mild in-office procedures like superficial chemical peels and microdermabrasion gently exfoliate the outermost layer of the skin. These treatments refine surface texture and address discoloration but do not penetrate deeply enough to stimulate the significant collagen remodeling needed to elevate the scar floor.
Advanced Procedures for Scar Revision
Significant improvement for boxcar scars requires clinical procedures that actively stimulate deep collagen production or physically alter the scar tissue. Microneedling, particularly when combined with radiofrequency (RF Microneedling), creates controlled micro-injuries deep within the skin to trigger a powerful wound-healing response. The addition of radiofrequency energy heats the dermis, dramatically amplifying collagen and elastin synthesis to remodel the scar from the inside out. This technique is effective for both shallow and moderate boxcar scars.
Laser resurfacing uses targeted light energy to either remove thin layers of skin (ablative lasers) or heat the underlying tissue (non-ablative lasers). Ablative lasers, such as fractional CO2, vaporize tissue and smooth the sharp edges of the boxcar. Non-ablative lasers stimulate collagen growth with less downtime.
Dermal fillers, typically composed of hyaluronic acid, offer an immediate solution by being injected directly beneath the scar to physically lift the depressed floor. Another highly effective procedure is subcision, which involves inserting a specialized needle beneath the skin to mechanically break the fibrous strands of scar tissue tethering the scar down. Subcision can be beneficial for boxcar scars that have a tethered component, allowing the scar to rise and new collagen to form in the released space. The best outcomes are often achieved through a combination therapy approach, blending procedures like microneedling, subcision, and laser treatments over a series of sessions.