Management of ALA-PDT Induced Pain Sensations

• Published in: Medical laser application 2003, Vol.18 (1), p.57-64
• Main Authors: Algermissen, Bernd, Osterloh, Dieter, Philipp, Carsten M., Berlien, H.-Peter
• Format: Article
• Language: English
• Subjects: air stream; ALA; anaesthesia; pain; PDT
• ISSN: 1615-1615; 1878-3228
• DOI: 10.1078/1615-1615-00088

In dermatology, photodynamic therapy (PDT) with topically applied 5-aminolevulinic acid (ALA) has proved to be an alternative option for the treatment of malignant and benign skin lesions. The main advantages compared with other therapeutical options are the excellent cosmetic results achieved and the low number of side effects. One of the main acute side effects is pain arising during ALA-PDT lasting for several hours. Pain seems to depend on the light source used (lamp vs. laser, wavelength), power or energy density applied, diameter of the irradiated field and localisation. Our hypothesis of the mechanism of pain induction postulates that the pain may be the result of a damage to epidermal nerve endings which had accumulated ALA or protoporphyrin IX (PPIX) in their membrane during application time of ALA. According to this hypothesis methods for pain reduction should deal with a minimising accumulation of PPIX in nerve endings/membranes, desensitisation of nerve endings or blockade of the nerve depolarisation. Local (topically, i.c., s.c.) or regional (s.c. blockade) anaesthesia, fan, water spray, air stream, pre-cooled air stream, systemic application of NSAID or opioids alone or in combination were used for pain reduction with different success. The number of studies dealing with the evaluation of ALA-PDT induced pain and methods for pain reduction is very low despite it is a problem of great importance. In our clinical practice pain reduction with pre-cooled air is used with great success and found general acceptance by the patients. Application of regional anaesthesia was only necessary in special regions e.g. the ear and opioids were mostly given to anxious patients. In general, selecting or developing modalities for pain reduction one should consider that a non-invasive technique such as the ALA-PDT should necessarily demand a non-invasive modality for pain reduction such as a pre-cooled air stream.