Trichloroacetic acid peels “used to be popular at one point. And then they just seemed to disappear,” said Dr. Fanous, speaking with DERM.city. This was in part because of the introduction of lasers for many of the applications peels had traditionally been used to treat.
However, the major reason trichloroacetic acid peels fell out of favour is that the results were unpredictable, he said, with some patients developing chemical burns or scarring.
“My feeling was that the problem with the peeling is not that the peel was not good, but that it was not done the right way,” Dr. Fanous said. Trichloroacetic acid peels have several advantages over lasers in certain applications, said Dr. Fanous, which is why he worked to develop a technique to improve outcomes with the peels.
“The most common indication for my type of peel is people who have spots on their face and their skin [quality] is not nice enough,” Dr. Fanous said. These are patients in the age range of 20 to 50 years who have sun damage other than wrinkles, uneven pigmentation, large pores and similar complaints.
“Nothing beats a peel as the simplest, most efficient technique to give a better look to all the skin of the face in one sitting,” said Dr. Fanous. Laser procedures are expensive, and it can be challenging to achieve a homogenous result across an entire face using them, he said. Standardized
Standardized approach includes evaluation, application
To ensure minimal adverse events to accompany those good results, Dr. Fanous developed a standardized approach to patient evaluation, skin classification, and application of the acid, all steps to improve control over the depth of the peel.
When Dr. Fanous performed these types of acid peels earlier in his career, he found that using Fitzpatrick skin type was a limited predictor of outcomes. Light-skinned patients with family backgrounds from northern Asia, in spite of whitish skin, react like darker-skinned patients from southern Asia to the acid peel, developing redness and discoloured spots.
He found that the region of the world the patient’s ancestors came from was a better predictor of skin response to the acid.
The newly published peel technique starts by assessing a patient’s skin type according to a genetico-racial skin classification Dr. Fanous previously published in The Canadian Journal of Plastic Surgery (Spring 2011; 19(1), which is available in open-access at http://owlyleUKu30eQmmD. A specific acid concentration is then selected based on that assessment and whether a light, medium, or strong peel is required for the patient’s skin. Finally, the acid is applied in a standardized ‘strip’ pattern over the face to ensure uniform coverage and exposure time.
“It used to be that what counted was the concentration,” said Dr. Fanous. “People would say that 30 per cent trichloroacetic acid peel is a light peel. 35 per cent is a medium peel, 40 per cent is a deep peel. And that was a big mistake because there are many factors that make the peel go deeper.”
Multiple passes over the same part of the face is one example, he said, noting that five passes with a 30% solution will result in a deeper peel than one pass at 40%.
Uniformity of timing is also crucial, he said, since it takes some time for the telltale whitening sign to appear, but that sign is temporary. Return to a swabbed area too soon before the sign appears, or too late when it has faded, and the practitioner might think that the peel has not worked and that an additional application of acid is required. The standardized strip technique in the published approach is intended to prevent such timing errors, Dr. Fanous said.
Start low if patient ancestry unclear
The paper reviews 923 trichloroacetic acid peels performed in 803 female patients (87.0%) and 120 male patients (13.0%) at a single academic setting between Jan. 1, 1996 and Nov. 1, 2015. Mean patient age was 41.59 years, and follow-up periods ranged from six months to 13 years (mean, 13 months).
In this case series of acid peels, there was a low incidence of complications. There were 54 patients (5.9%) who experienced persistent hyperpigmentation, 3 (0.3%) with mild telangiectasia, 2 (0.2%) with acute herpes virus infection, 2 (0.2%) with Staphylococcusinfection, and 1 (0.1%) with hypopigmentation.
For practitioners considering starting to perform these types of trichloroaacetic acid peels using Dr. Fanous’ technique, he recommends that if the physician is not confident with the classification system, or if a patient’s geographic background is unclear, it might be advisable to start with a peel strength one step lower than otherwise indicated—a medium peel instead of a heavy peel, or a light peel instead of a medium, for example.
“Of course, it is not ideal to do that, but for someone who is starting it is better to do one step less for about a year or so, and when that person is comfortable, they can go higher,” Dr. Fanous said.
Originally publishedin The Chronicle of Skin & Allergy (Aug. 2017; 23(5):page 1,8,25)