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DSAP - Disseminated Superficial Actinic Porokeratoses (porokeratosis)


DSAP patient's skin cleared or not?

RIGHT: Markus Böhm et al., University of Münster, Germany, recently described a patient with DSAP whose skin lesions responded to topical tacalcitol. The 40-year-old woman had multiple, red to brown, annular, keratotic lesions, up to 1 cm in diameter, which were symmetrically distributed on the extensor surfaces of the upper and lower arms (see figure). The lesions had increased in size and number during the last 3 years and were unresponsive to topical corticosteroids, salicylic acid, and tazarotene. After topical treatment with 0.0004% Tacalcitol once daily was started, pruritus (itching) soon ceased. Tacalcitol was well tolerated. After 3 months the lesions had faded substantially, and after 2 additional months they had vanished completely. DSAP lesions before and after topical treatment with Tacalcitol 0.0004% over a period of 5 months.

Webmaster's opinion: In looking at the photos I have to wonder if the doctor correctly diagnosed the problem. By default I am always skeptical of anything I read. Is this really DSAP? It's hard to make heads or tails from these low-resolution before and after photos. These spots look brown, with no redness. Keep in mind that misdiagnosis is common. If it was in fact DSAP then this is very promising because it suggests that DSAP spots are reversible! The problem is that I have not heard of a single report (in the guestbook or to me directly) of DSAP clearing from anyone who used D3 analogues like Tacalcitol (or Dovonex, etc). And I've been running this site since 2000.

Here's yet another article from the July 5, 2011 and Sept. 2012 issues of the International Journal of Dermatology which claims "successful" treatment of a patient with DSAP in Bulgaria using another D3 analog variant called Calcipotriol. Not sure what "successful" means. The July 2011 article was written by Ilko Bakardzhiev MD PhD1, Svetlana Kavaklieva MD2, and Georgy Pehlivanov MD PhD. My understanding is that Calcipotriol is the same drug as Dovonex. I have personally tried Dovonex to no avail and haven't received one single email from anyone whose DSAP cleared from using Dovonex or the European equivalent Calcipotriol. But according to Dr Böhm some patients respond well to Calcipotriol while others don't. I have been told that Dr Böhm says that results depend on how long the lesions have existed. This makes me wonder if these might have simply been cases of spontaneous resolution mistaken for "Calcipotriol success".

There are many variables to take into consideration when evaluating reports of treatment success or failure. Here's a few that come to my mind: 1) Everyone has different body chemistry. What works for one person might not work for 100 others. 2) Doctors perform differently (ex - when using lasers, freezing). 3) Patients may equate DSAP improvement due to use of medication when in fact it may have been an improvement simply due to sun avoidance. Remember that if you avoid the sun and wear SPF-100 you will see an improvement over time. 4) A patient's initial report of 'success" may be short lived. Clear or clearer skin may lapse back to the pre-treatment condition a few short years later. Medications like Efudex may cause threadlike borders of DSAP to diminish but only temporarily (as in my case). 5) In some cases I have to wonder if so called reports of "improvement" (from use of a medication) might only be due to the mere return to original condition (after looking at the harsh, unsightly effects of treatment for several months). 6) Patients can be misdiagnosed as having AK rather than DSAP and see improvement. 7) Patients with AK or psoriasis may have been misdiagnosed as having DSAP and thus reports of improvement (ex- from using Efudex) may be incorrect. 8) And finally one has to wonder if "successful" DSAP treatments are hoaxes posted by people who stand to gain financially.

Interestingly I've had a couple of patients report success with the yag laser as well as from freezing. The one who swore by freezing indicated that they had found a good doctor who was very skilled at freezing at just the right depth, whereas other previous doctors didn't go deep enough. The other patient who swore by the yag laser treatment was also pleased by how the laser went deep in killing off abnormal skin cells. This goes against some message board posts (that I read) in which some doctors had nothing but failure to report from use of lasers on DSAP. These doctors reported that the DSAP would just keep growing back. Furthermore I read of a skin graft experiment in which healthy skin was swapped with unhealthy DSAP skin. Unfortunately the DSAP grew through (like a weed that was not pulled out by the roots). The other location returned to normal as it was before. Now having heard this story it is hard for me to imagine that lasers or freezing would work.

I mostly get E-mails from patients who have tried all kinds of treatments to no avail. Some patients claim that freezing with liquid nitrogen seems to "improve" DSAP. Unfortunately lighter skinned people may be left with red scars. Recently someone told me that Aldara has been reported to "improve" DSAP. Another patient saw their skin completely clear up from use of a topical vitamin D3 analogue (which is actually used for psoriasis). This suggests that DSAP may not be just plain irreversible sun damage. New treatments for psoriasis on the horizon may possibly offer hope for DSAP. Some doctors believe that DSAP and psoriasis may be (to some extent) similar autoimmune disorders. Keep in mind that it came as an accident when it was discovered that use of Topical Vitamin D3 Analogues (like Dovonex, Tacalcitol) helped in the treatment of psoriasis. Who's to say that a DSAP treatment or combination of treatments can't be stumbled upon by using medications designed for other disorders.


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