Will TCA CROSS work for my ice pick scars?

By Dr Magnus Lynch
MA(Cantab) DPhil(Oxon) MRCS FRCP
Consultant Dermatologist & Dermatological Surgeon
Last updated 2026-08-08

TCA CROSS is a good option for deep ice pick scars and can also be an option for deep boxcar scars. More than one session is usually required, and the scar will become shallower and less noticeable rather than disappearing altogether.

An ice pick scar is narrow at the surface and narrows further with depth. A deep boxcar scar is wider, with steep walls dropping to a flat base. Both shapes defeat most treatments: laser resurfacing works on the surface and cannot reach the base, dermal filler cannot be placed accurately within a channel that fine, and subcision is designed for tethered scars and has nothing to divide. TCA CROSS works precisely because it is applied into the scar itself, reaching the base where the problem lies.

A very small quantity of trichloroacetic acid is applied to the scar using a fine applicator, and the treated points turn white almost immediately. Over the following one to two weeks they scab and heal, and Vaseline should be applied until healing is complete. Sessions are spaced six to eight weeks apart and the improvement is cumulative, each session lifting the base of the scar a little further. As the base lifts the scar typically broadens and flattens, which is what renders it less noticeable.

Improvement is partial and gradual. These are the most difficult scars to treat and their removal cannot be guaranteed. Where there are only a small number of very deep scars, punch excision is sometimes the better option, since removing the scar and closing the defect with a suture converts a pit into a fine line.

I always advise treating a small number of scars as a test first in order to reduce the risk of complications. The healing response to trichloroacetic acid varies between individuals, and a test session establishes how a particular patient's skin behaves before committing to fuller treatment.

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About Dr Magnus Lynch

MA(Cantab) DPhil(Oxon) MRCS FRCP

I am a London-based Consultant Dermatologist and Dermatological Surgeon. I am highly experienced in skin cancer diagnosis, Mohs micrographic surgery, acne, rosacea, acne scarring and laser treatments. I studied at the Universities of Cambridge and Oxford, and completed my dermatology training and Mohs fellowship at the prestigious St John's Institute of Dermatology. I graduated from medical school in 2003 and have worked exclusively in Dermatology since 2012.

I lead a research team at King's College London investigating the molecular biology of skin cancer. In recent years I have been involved in Media Appearances, including the Channel 5 series 'Skin A&E', where I perform skin surgeries and treat various skin conditions.

My NHS practice is at Guy's Hospital. I consult with private patients at OneWelbeck (near to Bond Street station) and on Harley Street. Book A Consultation.