Dermatology Times editorial advisor, Dr. Elaine Siegfried continues the discussion on isotretinoin with Jim Leyden, M.D., emeritus professor of dermatology at the University of Pennsylvania. In this final segment, the two discuss whether a waiting period is necessary before treating acne scars and the questionable existence of pityrosporum folliculitis.
Dr. Siegfried: A topic that is getting more publication recently and is relevant for my patients is the issue about patients who have had their acne clear but have residual scarring. What can you do about scarring? Is a wait period required prior to performing microdermabrasion, dermabrasion or laser therapy?
Dr. Leyden: I don’t see the need for the long wait period given that the pharmacokinetics of isotretinoin (Accutane) is that it’s out of the system in five days. However, the basis of the first pronouncement that you should wait for six months (later it was changed to a year) was a retrospective study of how patients did post-isotretinoin with dermabrasion. These dermatologists felt that the patients did not do as well as they would expect normally. For a typical dermabrasion on a non-acne patient, they acknowledged that they pre-treat the skin with topical Retin-A (tretinoin) and that has been shown to enhance re-epithelialization, but they believed there was a difference. This just got declared but it never made any sense to me, particularly in view of the pretreatment with topical retinoid.
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Dr. Siegfried: There were some studies that were recently published that looked at the impact of early versus delayed laser treatment and there’s absolutely no difference.
Dr. Leyden: There shouldn’t be.
Dr. Siegfried: One question I have has come out of a review of isotretinoin failures and what this could possibly be. One thing mentioned in the differential is pityrosporum folliculitis. What do you think about that?
Dr. Leyden: I am pretty sure it doesn’t exist.
Dr. Siegfried: It’s a pretty popular general belief.
Dr. Leyden: It’s good to have a diagnosis to explain something. One place I have seen something I thought was probably pityrosporum was in the Philippines, where it’s very hot and humid.
I saw a couple of patients there at a meeting that had interesting pustules on their upper chest and back. They were very unusual. None of them had Staph aureus; they did not look like Staph aureus; and they clearly weren’t acne.
It was the late Peyton Weary who first proposed this condition back in the ’70s. When ketoconazole became available systemically and topically, I said maybe you ought to do a controlled study with ketoconazole by mouth or topically and really work out the kinetics of what you think this is. Nothing like that was ever done. So it is a diagnosis that people make that I am pretty sure doesn’t exist in terms of real pathophysiology. But I could be wrong.
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Dr. Siegfried: We don’t really have a great way to confirm. The histologic findings are suggestive sometimes, but certainly not diagnostic.
Dr. Leyden: If you put people on a drug that’s only effect is to suppress the yeast ...
Dr. Siegfried: Yeah, we don’t really have one like that, and the ketoconazole, which has been suggested as the antifungal of choice, maybe because it’s lipophilic and gets into sebaceous glands better?
Dr. Leyden: This is all a guess. These are all best hypotheses. In dermatology, we have this tendency to say hypothesis frequently enough and then they become established facts, without that little step in between of demonstrating.