Minimal phototoxic dose (MPD) measurements for topical photochemotherapy using a semiautomated MPD tester.
Br J Dermatol
; 169(3): 687-9, 2013 Sep.
Article
em En
| MEDLINE
| ID: mdl-23607709
ABSTRACT
BACKGROUND:
The traditional method of assessing minimal phototoxic dose (MPD) prior to photochemotherapy with psoralen-ultraviolet A (PUVA) is inconvenient and cannot directly determine PUVA start doses. A handheld minimal erythema dose UVB tester can be modified by fitting a TL-10 UVA compact fluorescence lamp (CFL).OBJECTIVES:
To determine whether MPD testing is possible with a CFL and to calculate a fixed factor to convert observed MPD to PUVA-equivalent MPD.METHODS:
Patients had two sets of MPD tests performed on symmetrical, contralateral sites on the lower back. MPD test results from a panel of PUVA lamps were compared with MPD from the modified handheld tester. Additionally, a questionnaire survey was completed by 43 U.K. phototherapy units to assess routine practice concerning MPD testing prior to PUVA therapy.RESULTS:
Thirty-seven patients with psoriasis were recruited. Boston phototypes in the 31 with conclusive MPD reactions were I, four; II, 11; III, 12; and IV, four. The handheld MPD results were linearly related to the PUVA panel MPD results as follows PUVA MPD = 0·48 × handheld MPD + 0·17 J cm(-2). The measured PUVA MPD was 0·48 of the handheld MPD, not 0·15 as predicted by the published PUVA action spectrum.CONCLUSIONS:
The modified MPD tester is a convenient and safe method for PUVA MPD testing, overcoming many problems of the 'traditional method'. The difference between the PUVA and TL-10 lamps was lower than predicted from published studies. This suggests that formal re-evaluation of the erythema action spectrum for PUVA is now needed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Psoríase
/
Terapia PUVA
Tipo de estudo:
Clinical_trials
/
Observational_studies
/
Prognostic_studies
Limite:
Adolescent
/
Adult
/
Aged
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Br J Dermatol
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Reino Unido