How To Improve Acne Scars

Acne is an extremely common skin disease in both adolescents and adults that can result in lasting scarring.^[1] Even after acne pimples and cysts have healed or gone away, scars can persist and lead to disfigurement, insecurity, and even psychosocial effects such as depression. Hyperpigmentation, or skin darkening, can also occur in areas of previous acne lesions, but these skin changes can gradually fade away over time. 

Effective treatment of early signs of acne is the best way to prevent and limit scarring, but for many people treatment is challenging, and despite extensive treatment, acne scars can develop. Unfortunately, there is no one single medication or procedure to banish scars. Improving acne scars usually requires multiple treatments and approaches in order to achieve the best cosmetic results.

Why Does Acne Scarring Occur?

Acne lesions (pimples, pustules, cysts) trigger an inflammatory response within the skin. As the immune system works to clear and heal the lesion, there can be a change in how the skin makes collagen. This response to inflammation can lead to acne scarring in some people, but not necessarily everyone with acne.^[2]

Acne scars can be classified as either “atrophic” or “hypertrophic” based on how they look. Most acne scars are atrophic and look like indentations in the skin due to loss of collagen.^[3] On the other hand, hypertrophic acne scars look like hard raised bumps due to excessive collagen formation. Keloids can also form, growing beyond the original outline of the wound or acne lesion (unlike hypertrophic scars which stay within the original acne lesion border).^[4]

Different Types of Acne Scars

What Are the Treatment Options? 

It is important to understand that scars typically cannot be completely eliminated. The degree of improvement achieved with acne scar treatments depends on many factors, such as the type of scar (atrophic or hypertrophic), the depth of scars, scar location (facial scars are usually easier to treat than body scars), and the person’s skin color. In addition, multiple different treatments may be required and some treatments may result in “down-time” or a recovery period, such as after an intense laser treatment.^[5] There is not currently a first line of treatment that is considered better than others.^[6] 

Nonsurgical Procedures & Devices 

Ablative laser resurfacing

This is the best treatment for inducing remodeling of collagen using either a erbium: yttrium aluminum garnet laser (Er:YAG) or a CO_s laser. These lasers ablate the skin in strategic locations, leading to injury with the consequent remodeling of collagen and skin tightening, which improves scar appearance. This treatment must be done by a skilled expert and may require a one to two week recovery period.^[12] This laser treatment is helpful for rolling and boxcar type scars. This type of treatment should be performed carefully on those with darker skin color. 

Nonablative fractional laser resurfacing

This laser technique has a shorter recovery period than ablative laser resurfacing but may require more treatments. This laser treatment is helpful on rolling and boxcar type scars. 

Pulsed-dye laser

This laser treatment improves redness (erythema) of scars by specifically targeting blood vessels. Many people require three to four monthly sessions for optimal results.^[7] This laser can be used on all types of acne scars.

Intense-pulsed-light

These devices can also help reduce scar redness.^[8] This treatment can be used on all types of acne scars.

Injectable Fillers

Injectable soft tissue fillers can provide immediate improvement in scar appearance. The resulting appearance after injection with a soft tissue filler is highly dependent on the skill of the clinician, location of the scar, and choice of specific filler. The majority of injectable fillers provide only temporary results lasting one to two years, necessitating retreatment for continued improvement in scar appearance.^[14] This type of filler was studied for use on “distensible scars,” which are typically rolling and boxcar type scars.

Skin needling (aka microneedling)

A cylinder studded with tiny needles (each 1 to 2.5 mm long) can be rolled over the skin inducing pillars of injury through the skin.^[15] So far, this treatment has shown good results in clinical trials with minimal side effects.^[15] Microneedle devices with a motorized head are also available for use. Microneedles are good for rolling and boxcar type scars.

Surgical Procedures

Dermabrasion

Special tools such as a high-speed brush, diamond tip, or silicon carbide sandpaper can be used to etch away the epidermis around scar edges to improve their appearance.^[14] This may be useful for those with rolling or boxcar scars. This technique should not be used on those with darker skin color. This procedure is not to be confused with microdermabrasion (which does not treat scars). 

Punch excision

A punch biopsy tool (with a slightly larger diameter than the scar) can be used to remove the scar tissue all the way to the fat layer beneath the skin and the pit is then sutured closed.^[11] This is used more for ice pick type scars and can be used on some boxcar type scars.

Subcision

During this procedure, a needle or blunt surgical blade is inserted beneath the scar to break up fibrous scar tissue that may be causing an indented appearance. The goal of this treatment is for new collagen to grow beneath the area of subcision.^[10] This type of treatment is used more often on boxcar and ice pick type scars.

Chemical Peels

Chemical peels

Peels also stimulate collagen remodeling by causing slight injury to the skin. Chemical peels are classified based on their depth of skin penetration as either superficial (ex – salicylic, glycolic, or lactic acid peels), medium (ex – Jessner solution or 50% trichloroacetic acid), or deep (ex – phenol).^[13] Chemical peels are good for rolling type scars and some boxcar scars. These treatments should be performed carefully on those with darker skin color.

Chemical reconstruction of skin scars (CROSS technique)

With this specialized technique, 100% trichloroacetic acid (TCA) peel solution is directed into the base of the scars. The purpose of this method is to promote remodeling within the dermal layer of the skin.^[9] The CROSS technique can be used on ice pick type acne scars.

Special Precautions

There are a few circumstances when someone may not meet the criteria to begin treatment for acne scars. For instance, people who still have active acne lesions should first be treated to reduce acne and encourage healing. People who are taking or have recently taken oral isotretinoin (often referred to as Accutane) should be careful when receiving a scar treatment. Some individuals with naturally darker skin colors are at higher risk for post inflammatory skin darkening (hyperpigmentation) with some of these treatments.^[13]