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Pain during photodynamic therapy is associated with protoporphyrin IX fluorescence and fluence rate
Author(s) -
Wiegell S.R.,
Skiveren J.,
Philipsen P.A.,
Wulf H.C.
Publication year - 2008
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2008.08451.x
Subject(s) - protoporphyrin ix , photodynamic therapy , medicine , fluorescence , protoporphyrin , dermatology , fluence , chemistry , photochemistry , optics , physics , ion , porphyrin , organic chemistry
Summary Background Pain during photodynamic therapy (PDT) is a considerable problem that needs to be studied to improve this otherwise attractive treatment of skin diseases. Objectives To compare pain during PDT using two different fluence rates, and also to evaluate the association between pain and protoporphyrin IX (PpIX) fluorescence, lesion type, lesion preparation and lesion localization. Methods Twenty‐six patients with actinic keratoses (AKs) in different localizations and 34 patients with facial acne vulgaris were treated with methyl aminolaevulinate–PDT. Patients with acne were illuminated using two different fluence rates. Pain score during PDT and PpIX fluorescence prior to illumination were measured. Results The study showed that pain during illumination was associated with the PpIX fluorescence in the treatment area ( P = 0·0003, R 2 = 0·31). When using a fluence rate of 34 mW cm −2 patients with acne had a pain score of 6 [interquartile range (IQR) 5–7] compared with 8 (IQR 6–10) when using a fluence rate of 68 mW cm −2 ( P = 0·018). After correcting the pain score for PpIX fluorescence no differences in pain scores were found between first and second acne treatment, locations of AK lesions or between the two types of lesions. Conclusions Pain during PDT was correlated with the PpIX fluorescence in the treatment area prior to illumination. Pain was reduced using a lower fluence rate during PDT of acne.