TCA Cross is a dermatological procedure designed to address specific types of depressed acne scars. It involves the precise application of a high concentration of trichloroacetic acid (TCA) to the base of individual scars. This targeted approach helps to stimulate the skin’s natural healing processes, improving the appearance of the treated areas. The technique differs significantly from broader chemical peels.
The Science Behind TCA Cross
Trichloroacetic acid (TCA) is a chemical agent used in varying concentrations for skin treatments. In TCA Cross, very high concentrations, typically ranging from 70% to 100%, are utilized. The term “CROSS” stands for Chemical Reconstruction Of Skin Scars.
When TCA is applied to the scar, it causes a controlled chemical reaction that leads to the precipitation of proteins and coagulative necrosis of cells in the epidermis and dermis. This process creates a localized injury within the scar tissue. The immediate visible sign of this reaction is “frosting,” where the treated area turns white due to protein denaturation.
The controlled damage prompts the body’s natural wound-healing response. This response involves the stimulation of fibroblasts, which are cells responsible for producing new collagen and elastin fibers. Over several weeks to months, this new collagen production helps to elevate the base of the scar, making it shallower and less noticeable.
What Skin Concerns It Addresses
TCA Cross is effective for atrophic acne scars, which are depressed scars that result from a loss of tissue. It is particularly well-suited for ice pick scars, which are narrow, deep, and often extend into the dermis. These scars resemble small, deep holes in the skin.
The precise application of TCA to the base of these deep, narrow scars allows for targeted treatment without significantly affecting the surrounding healthy skin. In addition to ice pick scars, TCA Cross can also be used to improve the appearance of certain shallow boxcar scars and enlarged pores.
The Treatment Procedure
Before the TCA Cross procedure, the skin is typically cleansed thoroughly, and any makeup is removed to ensure proper adherence of the acid. The procedure involves the precise application of a high-concentration TCA solution directly into each individual scar.
A fine-tipped applicator, such as a wooden toothpick or a blunt-ended instrument, is used to deposit a tiny droplet of TCA into the base of each scar. Immediately after application, the treated scar will turn white, a phenomenon known as “frosting.” This frosting typically lasts for a short period, around 10 to 20 minutes.
The procedure is highly targeted, treating only the depressed scar tissue and preserving the surrounding skin. The duration of the treatment depends on the number of scars being addressed, usually ranging from 15 to 30 minutes. Most patients report a brief stinging or biting sensation during application, which subsides quickly.
Recovery and Potential Considerations
Following a TCA Cross treatment, frosting of the treated areas may persist for up to 12 hours. The skin around the treated scars often appears red and can be sore for 24 to 48 hours. Within two to three days, small scabs typically form over the treated sites.
These scabs are a normal part of the healing process and usually fall off naturally within three to seven days. It is important to avoid picking or prematurely removing these scabs to prevent potential scarring or infection. After the scabs detach, the newly healed skin may appear pink, which gradually fades over several weeks.
Aftercare involves keeping the treated areas clean and moist, often with a gentle emollient. Sun protection is particularly important, with daily use of a broad-spectrum sunscreen (SPF 30 or higher) recommended to minimize the risk of post-inflammatory hyperpigmentation, a temporary darkening of the skin. While hyperpigmentation can occur, especially in individuals with darker skin tones, hypopigmentation (lightening) is also a rare possibility.
Multiple sessions, typically spaced six to eight weeks apart, are often needed to achieve optimal results, with many patients requiring three to six treatments.