Topical metronidazole does not abate UVB-induced erythema.
BACKGROUND
The capacity of topical metronidazole to reduce erythema severity scores in rosacea has been attributed to its anti-inflammatory activity.


METHODS
Nine healthy subjects were irradiated on three 1-cm(2) areas on their volar forearm with 2 MEDs of UVB. Twenty-four hours later, one of the irradiated areas was treated daily with metronidazole 1% vanishing cream, one with the vehicle only and the third was left untreated (control). The intensity of erythema was measured, at 24, 48, 72 and 96 h after irradiation, by a Chromameter CR200 (Minolta, Japan) and expressed in the L*a*b* system. The a* parameter was taken as the measure of redness.


RESULTS
Overall, redness diminished over time in a linear way, but treatments did not influence it significantly.


CONCLUSIONS
In our vehicle, metronidazole 1% cream failed to abate the UVB-induced erythema. An activity other than the anti-inflammatory one should be suggested to explain the topical metronidazole efficacy in rosacea.
Guarrera
M
M
Department of Endocrinological and Metabolic Diseases, Section of Dermatology, University of Genoa, Italy. rebdermo@unige.it
Brusati
C
C
Rebora
A
A
D000279:Administration, Cutaneous; D000328:Adult; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D004890:Erythema / Q000188:drug therapy* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use*; D008875:Middle Aged; D009824:Ointments; D012867:Skin / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors; D016896:Treatment Outcome; D014466:Ultraviolet Rays / Q000009:adverse effects*
D000890:Anti-Infective Agents; D009824:Ointments; D008795:Metronidazole