What is TCA cross peel and how is it undertaken?

TCA CROSS is the chemical reconstruction of skin scars (CROSS) using trichloroacetic acid (TCA).  

The TCA CROSS procedure involves depositing small amounts of TCA at high concentration onto the surface of the atrophic scar. This causes a local inflammatory reaction leading to the formation of new collagen fibres. The aim is to improve the appearance of the scar by increasing collagen and reducing shadows cast over scar depressions.  

TCA CROSS can be useful in ice-pick acne scars.  

How many treatments are required? 
The number of TCA CROSS treatments required depends on the type, location and depth of the scar however multiple sessions are usually required. Intervals of at least 4 weeks in-between treatments are generally recommended.​ 


  • Patients who have received systemic retinoid therapy with the last 12 months (isotretinoin) 
  • Pregnancy 
  • Breast feeding 
  • Active bacterial or viral infection 

How do I prepare for the procedure? 

  • Avoid tanning and direct sun exposure for 2 weeks prior to each treatment 
  • Apply a sunscreen with SPF 50 or greater every day for the duration of treatments. 
  • Discontinue alpha hydroxy acids (AHA), Beta Hydroxy Acid (BHA) and retinoids 2-3 days prior to treatment. 
  • Treatment areas must intact.  

Side effects 

  • Frosting (whitening) of the scar surface will last up to 12 hours 
  • The skin around the treated sites may be red and hypersensitive for 24 to 48 hours 
  • After 2 to 3 days a small scab may develop, this should fall off after 3 to 7 days – do not pick off any scabbing 
  • He or she may wash as normal and may apply make-up if desired 
  • Sunscreen is recommended to reduce the chance of pigmentation. 


  • Prolonged redness and swelling 
  • Post-inflammatory hyperpigmentation (darkening of the skin)  
  • Hypopigmentation (lightening of the skin) 
  • Coalescence of adjacent scars to form larger scars 
  • Blistering 
  • Allergic reactions 
  • Acne outbreak or the activation of recurrent viral infections such as herpes simplex  may occur 
  • Infection 
  • Scarring 
  • Inefficacy​ 

For best results TCA CROSS may be combined with other treatments such as; 

  • Topical retinoids 
  • Filler 
  • Microneedling 
  • Laser treatments 
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