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Melanin differentially protects from the initiation and progression of threshold UV-induced erythema depending on UV waveband.
Photodermatol Photoimmunol Photomed. 2006 Aug; 22(4):174-80.PP

Abstract

BACKGROUND/PURPOSE

This study aimed to determine the relationship between various measures of constitutive skin pigmentation and erythema caused by solar-simulated UV (ssUV), 290 and 310 nm UV.

METHODS

Skin pigmentation was assessed clinically by skin typing as well as objectively by measurement of the melanin index (MI) by reflectance spectroscopy. Subjects having Fitzpatrick skin types I-IV were exposed to graded doses of ssUV and either narrowband 310 nm (n=70) or 290 nm (n=69) UV, and assessed 24 h after exposure. Minimal erythema dose (MED) was assessed visually as the lowest dose that caused minimally perceptible erythema. Susceptibility to further development of erythema with higher exposure doses was measured by the gradient of erythema dose-response curves. This was determined by linear regression using reflectance spectrometry data beyond the MED.

RESULTS

Although there was considerable variation within each skin type, MI and ssUV MED increased with increasing Fitzpatrick skin type. MI correlated with ssUV MED and 310 nm UV MED, but not 290 nm UV MED. There was also a significant negative correlation between MI and erythema dose-response gradients caused by ssUV, 310 and 290 nm UV.

CONCLUSION

Melanin situated near the basal epidermis may not protect from the initial development of threshold erythema caused by 290 nm UV because it penetrates poorly past the stratum corneum and is not well absorbed by melanin in vivo compared with 310 nm UV. Higher erythemal 290 nm UV doses may reach basal epidermal melanin, which may then afford protection against further 290 nm UV erythema.

Authors+Show Affiliations

Department of Medicine (Dermatology), Melanoma and Skin Cancer Research Institute, Royal Prince Alfred Hospital, University of Sydney, Sydney, Australia.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16869864

Citation

Phan, Tai A., et al. "Melanin Differentially Protects From the Initiation and Progression of Threshold UV-induced Erythema Depending On UV Waveband." Photodermatology, Photoimmunology & Photomedicine, vol. 22, no. 4, 2006, pp. 174-80.
Phan TA, Halliday GM, Barnetson RS, et al. Melanin differentially protects from the initiation and progression of threshold UV-induced erythema depending on UV waveband. Photodermatol Photoimmunol Photomed. 2006;22(4):174-80.
Phan, T. A., Halliday, G. M., Barnetson, R. S., & Damian, D. L. (2006). Melanin differentially protects from the initiation and progression of threshold UV-induced erythema depending on UV waveband. Photodermatology, Photoimmunology & Photomedicine, 22(4), 174-80.
Phan TA, et al. Melanin Differentially Protects From the Initiation and Progression of Threshold UV-induced Erythema Depending On UV Waveband. Photodermatol Photoimmunol Photomed. 2006;22(4):174-80. PubMed PMID: 16869864.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Melanin differentially protects from the initiation and progression of threshold UV-induced erythema depending on UV waveband. AU - Phan,Tai A, AU - Halliday,Gary M, AU - Barnetson,Ross Stc, AU - Damian,Diona L, PY - 2006/7/28/pubmed PY - 2007/1/5/medline PY - 2006/7/28/entrez SP - 174 EP - 80 JF - Photodermatology, photoimmunology & photomedicine JO - Photodermatol Photoimmunol Photomed VL - 22 IS - 4 N2 - BACKGROUND/PURPOSE: This study aimed to determine the relationship between various measures of constitutive skin pigmentation and erythema caused by solar-simulated UV (ssUV), 290 and 310 nm UV. METHODS: Skin pigmentation was assessed clinically by skin typing as well as objectively by measurement of the melanin index (MI) by reflectance spectroscopy. Subjects having Fitzpatrick skin types I-IV were exposed to graded doses of ssUV and either narrowband 310 nm (n=70) or 290 nm (n=69) UV, and assessed 24 h after exposure. Minimal erythema dose (MED) was assessed visually as the lowest dose that caused minimally perceptible erythema. Susceptibility to further development of erythema with higher exposure doses was measured by the gradient of erythema dose-response curves. This was determined by linear regression using reflectance spectrometry data beyond the MED. RESULTS: Although there was considerable variation within each skin type, MI and ssUV MED increased with increasing Fitzpatrick skin type. MI correlated with ssUV MED and 310 nm UV MED, but not 290 nm UV MED. There was also a significant negative correlation between MI and erythema dose-response gradients caused by ssUV, 310 and 290 nm UV. CONCLUSION: Melanin situated near the basal epidermis may not protect from the initial development of threshold erythema caused by 290 nm UV because it penetrates poorly past the stratum corneum and is not well absorbed by melanin in vivo compared with 310 nm UV. Higher erythemal 290 nm UV doses may reach basal epidermal melanin, which may then afford protection against further 290 nm UV erythema. SN - 0905-4383 UR - https://www.unboundmedicine.com/medline/citation/16869864/Melanin_differentially_protects_from_the_initiation_and_progression_of_threshold_UV_induced_erythema_depending_on_UV_waveband_ L2 - https://doi.org/10.1111/j.1600-0781.2006.00226.x DB - PRIME DP - Unbound Medicine ER -