A comparison of the dose-response relationship for psoralen-UVA erythema and UVB erythema

Cox, Neil; Farr, P.M.; Diffey, Brian

doi:10.1001/archderm.125.12.1653

Cited by 25 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As might be expected, susceptibility to burning in the clinical setting is related to the steepness of an individual patient's erythema dose-response curve (Sakuntabhai et al, 1993b). We have confirmed our previous observation (Cox et al, 1989) that PUVA erythema has a shallower dose-response curve than UVB erythema (by a factor of µ 2) and have shown that this difference is maintained even at the time of maximum erythema determined in this study (24 h for UVB and 96 h for PUVA).…”

Section: Discussionsupporting

confidence: 91%

The Time-Course of Psoralen Ultraviolet A (PUVA) Erythema

Ibbotson

Farr

1999

Journal of Investigative Dermatology

View full text Add to dashboard Cite

The time-course for the development of ultraviolet A-induced erythema in psoralen-sensitized skin differs from that caused by ultraviolet B or ultraviolet A but objective data are not available. During psoralen ultraviolet A therapy, the minimal phototoxic dose is determined 72 h after exposure, when psoralen ultraviolet A erythema is assumed to be maximal. This measurement is of fundamental importance in optimizing the therapeutic regimen. We examined a detailed time-course for development of psoralen ultraviolet A erythema in 16 subjects. The erythemal responses to ultraviolet B, ultraviolet A and psoralen ultraviolet A were assessed visually and using a reflectance device. Ultraviolet B erythema was maximal 24 h after exposure compared with subsequent time-points. Psoralen ultraviolet A erythema was evident at 24 h, with reduction in the median ultraviolet A minimal erythema dose from 14 to 5 J per cm2 in the presence of psoralen (p < 0.01; n = 9). Peak psoralen ultraviolet A erythema, assessed by minimal phototoxic dose, did not occur until 96 h or later in 75% of subjects. Using individual dose- response curves, we determined that only 67% of mean maximum psoralen ultraviolet A erythemal intensity had developed by 72 h. Furthermore, at the time of maximal erythema, the slope of the psoralen ultraviolet A dose-response curve was approximately 2-fold shallower than that for ultraviolet B-induced erythema. If assessment of psoralen ultraviolet A erythemal sensitivity had been made at 96 h instead of the conventional 72 h time-point, peak erythemal responses would not have been missed in any of the subjects. Based on these findings, it seems appropriate to consider whether psoralen ultraviolet A minimal phototoxic dose measurements should be performed 96 h after exposure.

show abstract

Section: Discussionsupporting

confidence: 91%

The Time-Course of Psoralen Ultraviolet A (PUVA) Erythema

Ibbotson

Farr

1999

Journal of Investigative Dermatology

View full text Add to dashboard Cite

show abstract

“…The slopes of the dose-response curves in response to UV-A1 irradiation appear similar to those reported in response to oral psoralen-UV-A 27 and narrowband UV-B 28 and less steep compared with broadband UV-B, 29 although comparisons between studies should be interpreted with caution. The shallow dose-response curve for UV-A1 erythema mayresultinlimitationinsubjectivevisualassessment,which relies on a threshold of visual detection and suggests that, when possible, objective measurement should also be carried out with construction of accurate dose-response curves.…”

Section: Commentsupporting

confidence: 71%

“…All volunteers were exposed to a geometric dose series of UV-A1 irradiation (7,10,14,20,28,40,56, and 80 J/cm 2 for those with skin types I and II, with an additional dose of 112 J/cm 2 , while omitting the lowest dose for those of skin types III and IV; 1.4 incremental factor) at 2 test sites (photoprotected lower back and inner forearm skin; 8ϫ1.5 cm 2 test areas).…”

Section: Irradiationmentioning

confidence: 99%

Dose-Response and Time-Course Characteristics of UV-A1 Erythema

Beattie

Dawe²,

Ferguson³

et al. 2005

Arch Dermatol

View full text Add to dashboard Cite

“…Perhaps this was just a chance finding. However, possibly, starting treatment with a lower dose, on the initial flatter part of the sigmoidal erythema dose response curve, 17,18 leads to less production of tolerance to the erythemogenic effects of higher doses given mid course (when most important erythema reactions occur) than does starting at a higher dose.…”

Section: Adverse Effects Other Than Erythemamentioning

confidence: 99%