Can topical retinoids improve the appearance of atrophic acne scars?

Atrophic acne scars = ‘indented’ areas of the skin where inflammation has most likely caused damage to the collagen in the dermis. There are 3 types - boxcar, icepick or rolling. Light reflects off the scars creating shadows and that’s why they are noticeable.

Though very difficult to treat, the method with the most success is anything that physically smooths the skin surface to take away the irregularities. We know that acne scars (of all types) are caused by inflammatory acne lesions that are not treated effectively. Therefore, the best way to prevent acne scars is with effective treatment and prevention of acne. Dreno et al (2018) published a fairly controversial paper in which they claim to show that the use of topical adapalene 0.3%/BPO 2.5% gel over 24 weeks can ‘reduce’ atrophic acne scars.

There is no question that the topical combination improves and prevents acne lesions but can it also IMPROVE the appearance of atrophic scars? Let’s have a look at the study. The trial is a split-face design over 24 weeks in 67 subjects – so each person applied the adap/BPO combo to one side and the vehicle to the other. Each subject had an average of 12 scars measuring more than 2 mm on each half of the face at the start. After 24 weeks, the average number of acne scars on the treated side went down to 9.5 and the average number on the vehicle side went up to 13.3.

The actual values for each patient were not provided – only the mean numbers. This was a very well-designed study but there are a couple of issues: No definition or description of what an ‘atrophic scar’ is was provided by the authors.

It is really difficult to differentiate scarring from acne and inflammation in a patient with moderate to severe acne – the actual inflammatory acne improved on both sides of the face over the 24 weeks and the treatment side improved more than the vehicle side (but interestingly the vehicle side had an over 50% improvement in both inflammatory and non-inflammatory acne, showing yet again how powerful the placebo/vehicle effect is).

Did they use photos of all the patients to do the scar count, to make sure that what they had originally thought was a scar was actually an acne lesion or resolving lesion? I am quite confident that with continued use of topical retinoids an improvement in dermal structure can occur but whether or not this would make a noticeable or substantial difference to atrophic acne scars, I’m not so sure.

Nevertheless, every potential gain helps and I always strongly advise my patients to continue using a topical retinoid once their active acne is clear. If it helps improve the appearance of atrophic scars, then that is great, but if your scars are problematic, you will probably require some sort of physical treatment as well.