The effects of a high-potency topical steroid on cutaneous healing of burns in pigs

Objective: Burns are dynamic injuries that tend to progress over the course of several days. Steroids inhibit the formation of vasoconstrictive prostanoids that may contribute to this progression of injury. The authors hypothesized that adding topical steroids to a standard antimicrobial agent would reduce the progression of burns and accelerate reepithelialization without increasing infection rates. Methods: This was a prospective, blinded, controlled, experimental trial. Forty-eight standardized second-degree burns were created by applying an aluminum bar preheated to 80degreesC to the flanks of isoflurane-anesthetized young pigs for 20 seconds. Three equal sets of 16 burns were randomly treated with silver sulfadiazine cream (SSD), clobetasol propionate 0.05% (CP), or both (SSD+CP). Daily dressing changes were performed for 14 days. Full-thickness biopsies were taken after injury and at one, two, seven, ten, and 14 days for blinded histopathological evaluation using hematoxylin and eosin (H&E) staining. The primary outcome was the % reepithelialization (REP) calculated by dividing the length of the neoepidermis by the section's total length (interobserver correlation = 0.99). Depth of injury was measured for each dermal element (collagen; epithelial, mesenchymal, and vascular cells; and vessel thrombosis). Comparisons across groups were performed using one-way analysis of variance (ANOVA). A repeated-measures ANOVA was used to compare injury depths over time. This study had 80% power to detect a 33-percentage point difference in REP across groups (two-tailed alpha = 0.05). Results: Pretreatment burn depths were similar across groups. While burn depth changed over time, there was no difference between the groups in burn injury progression. There was no difference across the groups in REP or infection rates at all times. Conclusions: Addition of a potent topical steroid to standard antimicrobial topical agents does not reduce burn depth or accelerate reepithelialization after burns.