Topical photodynamic therapy with 5-aminolaevulinic acid does not induce hair regrowth in patients with extensive alopecia areata.
BACKGROUND
Photodynamic therapy (PDT) is a new modality involving the administration of a photosensitizer, or photosensitizer precursor, followed by its activation with light to generate a therapeutic effect. 5-Aminolaevulinic acid (ALA) is a photosensitizer precursor that is transformed by cells into protoporphyrin IX (PpIX), which can in turn be activated by red light.


OBJECTIVE
To investigate the effect of PDT in alopecia areata (AA).


METHODS
In six patients with extensive AA, topical ALA lotion at 5%, 10% and 20% as well as the vehicle lotion alone were applied separately to different scalp areas, followed 3 h later by exposure to red light at each treatment session.


RESULTS
No significant hair growth was observed after 20 twice-weekly treatment sessions. A significant increase in erythema and pigmentation was observed for the three concentrations of ALA lotion vs. the vehicle, implying that a phototoxic PDT effect was achieved in the skin. In vivo fluorescence spectroscopy in one patient showed an increase in red PpIX fluorescence 3 h after ALA application followed by a decrease after light exposure. On fluorescence microscopy, bright red fluorescence was present in the epidermis and sebaceous glands, but not in the inflammatory infiltrate surrounding the hair follicle following ALA application.


CONCLUSIONS
PDT was ineffective in the treatment of AA.
Bissonnette
R
R
Division of Dermatology, Vancouver General Hospital and University of British Columbia, 835 West 10th Avenue, Vancouver, BC V5Z 4E8, Canada.
Shapiro
J
J
Zeng
H
H
McLean
D I
DI
Lui
H
H
D000328:Adult; D000506:Alopecia Areata / Q000188:drug therapy* / Q000503:physiopathology; D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006197:Hair / Q000254:growth & development; D006801:Humans; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D017211:Treatment Failure
D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid