TCA CROSS or chemical reconstruction of skin scars (CROSS) using trichloroacetic acid (TCA) is technique that allows focal treatment of acne scars. Ice pick scars and boxcars are ideal lesions for this procedure. A very high concentration of TCA solution is applied precisely on the scars using a sharp wooden toothpick or a syringe to induce inflammation and collagen production of these deep acne scars. A white frost will develop on the affected areas within 10 to 15 seconds, and burning sensation will be felt by the patient. After a 3 to 5 days, scabs will form. These crusts will fall off in 7 to 10 days revealing a shallower scar. Several treatment sessions may be required depending on the severity of the condition.
In my practice, I combine TCA CROSS with other procedures to hasten improvement. But, compared to other procedures, I only do TCA CROSS every 6 to 8 weeks. I prefer to give the skin time to adequately heal. I find that if I do TCA CROSS within a short interval, the skin will improve depth-wise, but will develop hyperpigmentation. :-O