Erythema action spectrum of topical 8-methoxypsoralen-sensitized skin re-evaluated: implications for routine clinical practice.
Br J Dermatol
; 174(1): 131-5, 2016 Jan.
Article
em En
| MEDLINE
| ID: mdl-26383592
ABSTRACT
BACKGROUND:
Published methodology used to determine psoralen plus ultraviolet A (PUVA) erythemal action spectrum does not reflect current clinical practice for psoralen sensitization. We re-evaluated the PUVA action spectrum using aqueous 8-methoxypsoralen (8-MOP) 2·6 mg L(-1) as used routinely in current clinical practice.OBJECTIVES:
To determine the UVA erythema action spectrum of topical 8-MOP-sensitized normal skin.METHODS:
Twenty healthy volunteers with skin phototypes I-V were recruited. Forearms were psoralen-sensitized at 37 °C for 10 min. Six UVA irradiations at 10-nm intervals between 325 and 375 nm were randomly allocated to forearm sites and were applied using a 10-nm bandwidth irradiation monochromator. The visual minimal phototoxic dose (MPD) was recorded on each site at 96 h.RESULTS:
Volunteer Boston phototypes were I, n = 2; II, n = 6; III, n = 6; IV, n = 5 and V, n = 1. The mean MPD (J cm(-2) ) for all subjects at each wavelength was as follows 325 nm, 0·64 (SD 0·37); 335 nm, 0·80 (SD 0·58); 345 nm, 0·96 (SD 0·55); 355 nm, 1·50 (SD 0·85); 365 nm, 2·19 (SD 0·90); and 375 nm, 2·89 (SD 1·06). Therefore, the relative sensitization at each wavelength (erythemal action spectrum) was 1, 0·83, 0·67, 0·43, 0·29 and 0·22. There were significant differences between the PUVA erythemal effectiveness at different wavelengths but none between skin types.CONCLUSIONS:
This study has established the erythemal action spectrum for bath/soak PUVA therapy as is currently performed. In all volunteers, the peak sensitivity was at 325 nm. All volunteers showed a similar trend across the wavelengths studied irrespective of skin type. The determination of the action spectrum for PUVA-induced erythema is important as it permits reliable estimates of erythemal efficacy of any UVA source where the emission spectrum of the lamp is known or can be measured.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Terapia PUVA
/
Fármacos Fotossensibilizantes
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Eritema
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Metoxaleno
Tipo de estudo:
Clinical_trials
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Etiology_studies
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Br J Dermatol
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Reino Unido