Histologic evaluation of preauricular and postauricular human skin after high-energy, short-pulse carbon dioxide laser
Cotton, J.; Hood, A.F.; Gonin, R.; Beesen, W.H.; Hanke, C.W.
Archives of Dermatology 132(4): 425-428
1996
ISSN/ISBN: 0003-987X PMID: 8629845 Document Number: 457221
Fifty patients with severe recalcitrant plaque-type psoriasis were randomized to receive treatment with either oral tacrolimus (FK 506) (n=27) or placebo (n=23) for 9 weeks. The two treatment groups were comparable with respect to baseline demographic data. The initial dose was 0.05 mg/kg per day and, in cases of insufficient efficacy, could be increased to 0.10 and 0.15 mg/kg per day at the end of weeks 3 and 6, respectively. Treatment efficacy was based on the percentage reduction in the Psoriasis Area and Severity Index compared with baseline data. Patients were defined as responding to therapy if the percentage change in the Psoriasis Area and Severity Index from baseline after 3, 6, and 9 weeks was 20% or greater, 45% or greater, and 70% or greater, respectively. Safety was assessed on the basis of all adverse events reported. At the end of week 9, tacrolimus+-treated patients had a significantly greater reduction in the Psoriasis Area and Severity Index than did placebo-treated patients (tacrolimus, -83; placebo, -47; P<.02). Similar numbers of patients in both groups responded to therapy at the end of week 3, but at the end of weeks 6 and 9, more tacrolimus-treated patients responded to therapy (week 6 ,12 tacrolimus- and six placebo-treated patients; week 9, 12 tacrolimus- and three placebo-treated patients). Diarrhea, paresthesia, and insomnia were the most frequently reported causally related adverse events in the tacrolimus-treated group. All of the reported adverse events were mild or moderate in severity, and all resolved without a change in study medication. Compared with placebo, tacrolimus is efficacious in the treatment of recalcitrant plaque-type psoriasis. Despite its growing use in dermatalogic surgery, the effects of high-energy, short-pulse carbon dioxide laser on human skin have not been well documented. To study the histologic effects of this high-energy, short-pulse CO2 laser on human skin and to compare these changes with the effects of standard chemexfoliation procedures. Twenty-four hours after laser administration, there was extensive epidermal necrosis and coagulative change in the superficial papillary dermis. With increasing doses of laser energy, there was a statistically significant increase in the depth of dermal wounding (P<.001 for days 1 and 3, F-test). Reepithelialization occurred in most specimens by day 3. By day 90, most specimens showed a subepidermal dermal repair zone consisting of compact new collagen fibers overlying collagen with evidence of solar elastosis. This high-energy, short-pulse CO2 laser produces morphologic changes similar to those seen with medium-depth chemical peels. This laser can ablate skin precisely and bloodlessly with little interference in the wound healing process, suggesting that it may serve as an alternative treatment for photoaged skin.