Acne Scars

Treat Acne Scars

TCA CROSS Acne Scars

What is TCA CROSS Acne scars treatment and what does it stand for?

TCA is short for Trichloroacetic acid. TCA is a medium to deep chemical peel that has been used extensively to treat scars, wrinkles and photo aging.

CROSS is an acronym for Chemical Reconstruction of Skin Scars.

The CROSS technique uses high concentration TCA to denature the proteins at the deeper layers of the skin where scar tissue is found. This process stimulates collagen synthesis, skin thickening and a resultant improvement in your acne scar appearance.

For deep scarring, even the most powerful laser resurfacing is rendered ineffective because of the limitation of the laser penetration within the skin.

TCA CROSS acne scars treatment is a specialised focal technique to treat selected deep scars effectively and safely, with minimal downtime.

tca cross acne scars treatment for ice pick scars
Ice Pick and Pitted Acne Scars

What kind of scars respond best to TCA CROSS?

Different acne scars require specific treatments. TCA CROSS is most effective for:

  • Ice pick scars
  • Deep boxcar scars
  • Deep rolling scars
  • Atrophic and Mixed Acne Scars
  • Enlarged Pores
(A) Untreated Scar (B) 65% TCA CROSS (C) 100% TCA CROSS

How is TCA CROSS different from full face chemical peeling?

A wide variety of agents have been shown effective for superficial peeling. This includes alpha hydroxy acids (AHA), beta hydroxy acids (BHA) and Jessner’s solution. All this products work by exfoliating the skin by increasing turnover of the skin cell cycle. These superficial peels are mainly used for full face treatments, to improve skin texture and even out pigmentation.

For deep acne scars, a superficial peel will not be effective. Moreover, it is not only impractical, but also risky to use deep peels to the entire face. TCA CROSS acne scars treatment therefore acts as a bridge of targeting selected deep acne scars for resurfacing, making it an effective and safe procedure.

What Happens After TCA CROSS For Acne Scars?

The TCA CROSS application causes proteins in the cells to denature and coagulate in the epidermal layer. The dermal collagen undergoes a process known as necrosis (cell death). Following this, the skin cells in the epidermal layer renew and regrow. The collagen in the dermal layer undergoes re-organization over months. Moreover, there is thickening of the dermal layer and increase in dermal structural elastin and glycosaminoglycans as well.

A study has documented the changes following TCA CROSS in the skin under histological analysis. Using special staining methods, researchers showed that TCA CROSS activated fibroblasts (cells that produce collagen), increased epidermal thickening and dermal collagen content.

How is TCA CROSS performed?

After an initial assessment is made to ensure you are safe to proceed with the TCA CROSS acne scars procedure, your face is cleansed to remove any impurities and to facilitate absorption of the chemical peel. The concentration of the TCA CROSS chosen depends on the individual skin type and scar depth. Studies have shown that TCA concentration up to 100% to be safe and effective.

An applicator is used to apply the TCA within the base of the selected scar tissue. The treated area will turn white (frost), which signals that the proteins in the skin are being denatured. You many feel a warm heating sensation, but the procedure is well tolerated for most individuals. This process is repeated to treat each scars individually. An antibiotic ointment is applied after the procedure to allow healing and to reduce the risk of infection.

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Toothpick or Syringe Technique?

The chemical reconstruction of skin scars (CROSS) by the syringe technique is another method of treating ice pick scars. In this study, the syringe technique involves filling a 1ml syringe with TCA and delivery via a fine gauge needle. The needle may be bent to allow the flow rate of the TCA to be regulated. The main advantage of the syringe technique is only faster treatment time. However, the disadvantages are difficulty manipulating the flow of TCA on small scars and an increased risk of squirting onto the treatment area. 

In our experience, the toothpick method gives better control although treatment time may be longer. There is no advantage over the clinical outcome when using one method over the other. Your safety is always a priority when it comes to any medical treatment.

After the procedure

The frosting (white areas) will remain for up to 12 hours, and the surrounding skin will appear red and swollen for up to 24-48 hours.  A scab will develop in a few days, which typically falls off within 3-7 days. It is important not to pick at the scab to allow healing and prevent further scarring.

An antibiotic ointment is applied regularly until healing is complete, and strict sun avoidance is necessary to prevent pigmentation around the treated area.

How many treatments will I need?

The number of treatments you may need will depend on the severity of your scarring and your healing response to the treatment. On average three to six TCA CROSS acne scars treatments may be required over a 3-6 month period for better results. Interval between TCA CROSS treatment is about 6 weeks.

acne free skin

Post Procedure Effects of TCA CROSS

While TCA CROSS is considered safe and effective for all skin types, and is generally a well tolerated procedure, some individuals may experience:

  • Temporary skin redness/swelling
  • Skin colour changes (Hyperpigmentation or Hypopigmentation which is rare)
  • Poor response to the treatment (This may be due to delayed or inadequate collagen synthesis)
  • Infection (rare)

For Asian type skin, it is important to avoid the sun and use a sunscreen regularly to avoid hyperpigmentation (darkening at the treatment areas).

How much improvement can I see following TCA CROSS?

Individuals that respond best to TCA CROSS are the ones with severe deep scarring. On average, most individuals should see a 1-2 grade improvement in their acne scarring over a 6 to 9 month period.

Will combining with other treatments further improve my acne scars?

TCA CROSS is often combined with other acne scar treatments to give better results. For example, subcision to release the deep bands of the acne scars may be performed at the same session.

For mixed acne scarring, the Acne Scar Removal Program offers a comprehensive treatment option to manage the wide variety of acne scar types. Different scars require different approaches, and a synergistic effect is seen with combined treatment. Generally, we treat the deep scars at the initial stages of acne scar revision before we perform fractional resurfacing of the skin. 

More Information:

Dr Moses Ng dermatologist

TCA Cross

TCA CROSS for Acne Scars is one the most common procedures performed in my clinic. Ice pick scars are one of the deepest atrophic scar, and the treatment to resurface such scars must reach the correct depth. While fractional resurfacing lasers are good for superficial atrophic and rolling scars, they are not the treatment of choice for ice pick/pitted scars. I have performed numerous TCA CROSS in darker skin types, and found it safe, with most cases recovering in less than 7 days.

Dr. Moses Ng

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Related Information:

  1. Lee JB, Chung WG, Kwahck H, Lee KH. Focal treatment of acne scars with trichloroacetic acid: chemical reconstruction of skin scars method. Dermatol Surg 2002;28:1017-21
  2. Agarwal N, Gupta L, Khare A et al. Therapeutic response of 70% Trichloroacetic acid CROSS in atrophic acne scars. Dermatol Surg May 2015; 41(5):597-604S. B. Cho, C. O. Park, W. G. Chung, K. H. Lee, J. B. Lee, and K. Y. Chung,
  3. Histometric and histochemical analysis of the effect of trichloroacetic acid concentration in the chemical reconstruction of skin scars method, Dermatologic Surgery, vol. 32, no. 10, pp. 1231–1236, 2006.
  4. Logan, I. 2015. TCA CROSS. [online] Available at: