| dermatology | ARTICLE as ala is hydrophilic and the esterified form mal is
more lipophilic, it was anticipated that mal might penetrate more deeply into lesions. ala is reported to result in higher PpIX levels than mal, but with less selectivity for inflammatory acne lesions compared with healthy tissue33
. In a split-face comparison of 15 patients
with inflammatory acne, no difference was found between ala–Pdt and mal–Pdt (ala/mal 3-hour, 632 nm, 37 J/cm2
, 34 mW/cm2 ) with regard to treatment
efficacy, whereas ala–Pdt resulted in more severe adverse effects after treatment33
. Four randomised studies have been reported of mal–
Pdt for acne. In an investigator-blinded study of 36 patients with moderate-to-severe acne, two sessions of Pdt (mal 3-hour, 635 nm, 37 J/cm2
, 34 mW/cm2 ) at 2-week
intervals resulted in a significant 69% reduction in inflammatory lesions after 3 months. However, no reduction was seen in non-inflammatory lesion counts. all patients experienced moderate-to-severe pain during treatment and developed severe erythema, pustular eruptions, and epithelial exfoliation (18). a randomised, split-face comparison study of 15 patients
of ala–Pdt and mal–Pdt (3-hour, single treatment, dosimetry as above) achieved a 59% reduction in inflammatory lesions after 3 months in both groups, but with moderate-to-severe pain and pustular reactions, which were more severe in the ala–Pdt-treated areas37 a further randomised, placebo-controlled, split-face study of Pdt (mal 3-hour, 635 nm, 37 J/cm2
. ) treated 30
patients with moderate-to-severe facial acne, with Pdt repeated after 2 weeks. Nodular and cystic lesions were prepared using a small cannula to facilitate cream penetration. a greater reduction in inflammatory lesions was observed at 12 weeks following Pdt (54% vs 20%)12 a blinded randomised study of Pdt using IPl in asian
.
skin, with mal applied for only 45 minutes, failed to show significant improvement of moderate inflammatory acne compared with controls40
. With regard to the protocol of application
of the photosensitiser, most trials have evaluated 3-hour applications with either ala or mal11, 17–19, 35, 37
, and only a few
controlled trials have evaluated short term application times of 15–30 minutes15, 38, 40
this concentration has been reduced to mal 4% in an open uncontrolled trial in acne, showing good efficacy, better tolerance, and therefore improved patient acceptance41
. Pdt has been used for patients with acne from all skin
phototypes. Post-inflammatory hyperpigmentation has been reported for subjects with Fitzpatrick skin types IV– VI, irrespective of the treatment regimen. It has been proposed that less aggressive therapy (i.e. with lower mal/ala concentrations, shorter incubation times, or longer treatment intervals) is likely to be far better tolerated by darker skin types13
. Pdt using 5-ala 0.5% liposomal spray It has been proposed that less aggressive therapy is likely
to be far better tolerated by darker skin types.
or 90 minutes41 .
PpIX production is directly related to how long the sensitiser has been in contact with the skin42
. Contact
times of 3–4 hours were associated with significant patient drop-out as a result of pain, pustular eruptions, exfoliation, oedema, and erythema11, 14, 19, 37, 43
. ‘Short contact’ times of
15–90 minutes seem to be associated with milder and less frequent adverse effects15, 40
mal–Pdt sessions (37 J/cm2
. a study of 44 patients treated with four ), at 2-week intervals, with and
. Some researchers do
not report using occlusion for mal–Pdt in their patients with acne40, 41
without 3-hour occlusion, showed median reduction of inflammatory lesions by 58% and 55.8% respectively44
.
ala is consistently used with occlusion because of its hydrophobic nature. ala and mal are commercially available in concentrations of 20% and 16% respectively.
and IPl in combination with topical peeling agents resulted in a mean improvement of 68% in the total number of lesions after a mean period of 7.8 months and a mean number of 5.7 treatments45
. liposomes are used in the treatment of hair follicle and sebaceous
gland associated disorders because of their potential to carry lipophilic drugs and hydrophilic drugs such as 5-ala into the pilosebaceous unit46–48
. a systematic review of optical treatments for acne
vulgaris concluded that they should not be included among first-line treatments4
. For pulsed-dye lasers, a
randomised controlled trial showed an improvement of 49% on inflammatory acne lesions 12 weeks after one treatment9
of IPl-assisted Pdt versus IPl in two19
. Controlled trials also showed superior efficacy and three38
treatment
sessions with topical ala. In another trial of adapalene and four sessions of IPl — with or without pretreatment with mal for 30 minutes — Pdt therapy did not significantly improve inflammatory acne when compared with adapalene alone40
. there is no other study comparing Pdt with ala or mal to a standard topical acne
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