Confocal histopathology of irritant contact dermatitis in vivo and the impact of skin color (black vs white).
BACKGROUND
The pathogenesis of irritant contact dermatitis and its modulation according to skin color is not well understood. Reflectance confocal microscopy (RCM) enables high-resolution, real-time, in-vivo imaging of human skin.


OBJECTIVE
The goal of our study was to use RCM to determine whether susceptibility to irritant contact dermatitis differs between black and white skin.


METHODS
Participants were placed in groups on the basis of skin color and the volar aspects of their forearms exposed to 1% and 4% sodium lauryl sulfate using Finn Chambers (Allerderm Laboratories Inc, Petaluma, Calif). They were evaluated at 6, 24, and 48 hours by RCM, transepidermal water loss, laser Doppler velocimetry, and routine histology.


RESULTS
Participants with white skin had more severe clinical reactions than those with black skin. RCM revealed microscopic changes even without clinical evidence of irritation. Confocal features included parakeratosis, spongiosis, perivascular inflammatory infiltrate, and microvesicle formation, and these features were confirmed by routine histology. Also, participants with white skin had greater mean increases in transepidermal water loss after exposure to 4% sodium lauryl sulfate than did participants with black skin.


CONCLUSIONS
In-vivo RCM can track early pathophysiologic events revealing differences between black and white skin during the development of irritant contact dermatitis, and may support the theory that those with black skin are more resistant to irritants.
Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Shari P
SP
Hicks
Kirsty J
KJ
Swindells
Maritza A
MA
Middelkamp-Hup
Martine A
MA
Sifakis
Ernesto
E
González
Salvador
S
González
D000293:Adolescent; D000328:Adult; D044383:Black People; D003877:Dermatitis, Contact / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007509:Irritants / Q000009:adverse effects; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D012307:Risk Factors; D012880:Skin Pigmentation; D044465:White People
D007509:Irritants