Dramatic clearance of a recalcitrant acral viral wart using methyl aminolevulinate-red light photodynamic therapy

A 20-year-old man presented with a 3-month history of a viral wart located on his right thumb. Cryotherapy was administered weekly to the wart over 5 months without any significant improvement. A decision was made to treat the wart with red light photodynamic therapy (PDT) using topical methyl aminolevulinate (MAL) administered as three treatments 1-week apart. The patient was reviewed 4 weeks after the third treatment and the wart was found to have cleared completely. Three months after the last treatment, there remained no clinical evidence of recurrence of the wart. Pain was the main problem with the treatment but it was tolerable. Although the successful treatment of recalcitrant acral viral warts with PDT using 5-aminolevulinic acid (ALA) is well documented, this is the first report of the successful PDT treatment of a recalcitrant acral viral wart using the methylester derivative of ALA. We believe that MAL is a valuable alternative photosensitizer to ALA as it is more lipophilic, has better penetration and causes less pain.