Is superficial burn caused by ultraviolet radiation (sunburn) comparable to superficial burn caused by heat--a histomorphological comparison by in vivo Reflectance-Mode-Confocal Microscopy.
BACKGROUND
Regardless of the underlying cause, both sunburn and superficial thermal injuries are classified as first-degree burns, since data on morphological differences are scarce. Reflectance-Mode-Confocal Microscopy (RMCM) enables high-resolution non-invasive investigation of the human skin.


OBJECTIVE
We studied in vivo histomorphological alterations in both sunburn and superficial thermal injuries using RMCM.


METHODS
Ten patients (6 female, 4 male; aged 28.4 +/- 10.6 years) with first-degree thermal-contact Injuries (TI group), and 9 sunburned patients (SB group; 7 female, 2 male; aged 30.2 +/- 16.4 years), to a maximum extent of 10% of the body surface were evaluated 24 h after burn injury using RMCM. The following parameters were obtained using RMCM: stratum corneum thickness, epidermal thickness, basal layer thickness, granular cell size.


RESULTS
Compared to the controls (12.8 +/- 2.5 microm), stratum corneum thickness decreased significantly to 10.6 +/- 2.1 microm in the TI group, whereas it increased significantly to 16.4 +/- 3.1 microm in the SB group. The epidermal thickness did not differ significantly in the TI group (47.9 +/- 2.3 microm) and SB group (49.1 +/- 3.5 microm); however, both increased significantly compared to their respective controls (41.8 +/- 1.4 microm). The basal layer thickness increased more in the SB group compared to the TI group (17.9 +/- 1.4 microm vs. 15.6 +/- 1.1 microm). Both differed also significantly compared to their controls (13.8 +/- 0.9 microm). The granular cell size increased significantly in both groups compared to the controls (731 +/- 42 microm); however, a significantly higher increase was observed in the TI group (852 +/- 58 microm) compared to the SB group (784 +/- 61 microm).


CONCLUSIONS
Ultraviolet radiation seems to influence predominantly deeper epidermal layers, whereas heat-induced burns affect more superficial epidermal layers. The term 'First-degree burn' should not be used synonymously for sunburn and superficial thermal burn injuries. Conflicts of interest None declared.
Altintas
M A
MA
Department of Plastic, Hand and Reconstructive Surgery, Medical School Hannover, Hannover, Germany. altintas.mehmet@mh-hannover.de
Altintas
A A
AA
Guggenheim
M
M
Busch
K H
KH
Niederbichler
A D
AD
Aust
M C
MC
Vogt
P M
PM
D000328:Adult; D002056:Burns / Q000503:physiopathology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D013471:Sunburn / Q000503:physiopathology*