LISBON – Contrary to conventional wisdom, atrophic acne scars may arise from what was clinically normal skin 3 months earlier.
Inflammatory acne lesions clearly play a major role in atrophic scarring, but scars can arise from erythematous macules and closed comedones as well.
"And it’s also important to emphasize that we’re able to identify atrophic scars arising from clinically normal skin," Dr. Sewon Kang said at the annual Congress of the European Academy of Dermatology and Venereology, during a session sponsored by Galderma.
His study of the natural history of acne over a 12-week time frame used computer-assisted spatial alignment and serial high-definition digital photographs to track new lesions and atrophic scarring in 25 subjects with untreated mild to moderate facial acne. Participants were formally assessed every 2 weeks.
Closed comedones accounted for 37% of all lesions, followed by erythematous macules at 26%, inflammatory papules at 15%, open comedones at 12%, with pustules and nodules accounting for the rest.
"Both non- inflammatory as well as inflammatory acne lesions need to be addressed in order to prevent the most terrible sequelae of acne: the formation of scars."
At 12 weeks, a total of 219 inflammatory lesions were present: 176 papules, 35 pustules, and 8 nodules. Working backward via the serial tracking system, Dr. Kang and coworkers determined that 41% of the inflammatory lesions were preceded by closed comedones, 13% by open comedones, 12% from erythematous macules, and 6% from ice pick scars. Importantly, 28% of inflammatory lesions arose from clinically normal-appearing skin, said Dr. Kang, professor and chair of the department of dermatology at Johns Hopkins University, Baltimore.
Also present at 12 weeks were a total of 104 atrophic scars as agreed upon by at least two of the three independent examining dermatologists. Nearly 70% were ice pick scars, 30% were boxcar acne scars, and 2% were rolling scars.
Of note, 23 of the 25 study participants had one or more acne scars at 3 months of follow-up.
In all, 30% of the scars were already present at baseline. Another 20% arose from inflamed papules or pustules or from closed comedones. But fully half of the scars arose from noninflammatory lesions.
The clinical implication of these findings is that aggressive treatment should be prescribed from the outset in acne patients – even in those with mild disease – to prevent acne scarring.
"Both noninflammatory as well as inflammatory acne lesions need to be addressed in order to prevent the most terrible sequelae of acne: the formation of scars," said Dr. Kang.
Based upon these findings, he said he favors multimodal acne therapy with a retinoid, an antimicrobial agent, and benzoyl peroxide.
Dr. Kang is a paid speaker for Galderma.