Dermatologie Photodynamic therapy is painful: any way around it ?
Pain associated with aminolevulinic acid-photodynamic therapy of skin disease.
Warren CB, Karai LJ, Vidimos A, Maytin EV.
J Am Acad Dermatol. 2009 Dec;61(6):1033-43. doi: 10.1016/j.jaad.2009.03.048.
It is used for the treatment of actinic keratosis (AK), skin cancers and more and more for conditions such as acne vulgaris.
Unfortunately the action of the light on the photosensitizing substance can be painful.
It also shows the evidence in the literature of the pain derived from ALA versus MAL.