83337
document
The degrees of UVB-induced erythema and pigmentation correlate linearly and are reduced in a parallel manner by topical anti-inflammatory agents . To examine whether it is possible to evaluate the degree of ultraviolet B ( UVB ) -induced inflammation by measuring the degree of hyperpigmentation , we investigated the relationship between UVB-induced erythema and the subsequent pigmentation quantitatively . At 24 h and 7 d after irradiation with erythemogenic doses of UVB to the backs of 16 Japanese subjects , the degree of induced erythema ( delta erythema index ) and that of pigmentation ( delta melanin index ) were examined by an image analytic method using a videomicroscope interfaced with a computer . The relationship between two indices was linear in each subject , and the correlation coefficient was 0.83 when evaluated using whole data . The slope of the regression line for the delta melanin index against delta erythema index tended to become steeper as non-irradiated skin color became darker ( r = 0.63 ) , suggesting that more efficient melanogenesis takes place after the same level of inflammation in the subject with darker skin . Both erythema and hyperpigmentation were suppressed significantly and in a parallel manner by corticosteroids and indomethacin applied topically immediately after UVB irradiation . These results imply that the post-inflammatory hyperpigmentation correlates closely with the severity of the prior inflammation and that chemical mediators released in the inflammatory process have considerable influence on the melanogenesis . We conclude that the measurement of UVB-induced hyperpigmentation can be utilized for the assessment of topical anti-inflammatory agents , unless these have direct actions on the tyrosinase activity of melanocytes .
83338
Intervention_Pharmacological
topical anti-inflammatory agents .
83339
Intervention_Pharmacological
corticosteroids
83340
Intervention_Pharmacological
indomethacin
83341
Intervention_Pharmacological
topical anti-inflammatory agents
83342
Outcome_Other
erythema and hyperpigmentation
83343
Outcome_Physical
post-inflammatory hyperpigmentation
83344
Outcome_Physical
UVB-induced hyperpigmentation