ALA/PDT in the treatment of actinic keratosis: spot versus confluent therapy. 
Actinic keratosis (AK) represents commonly occurring, atypical keratinocytic proliferations confined to the epidermis.  While it is the standard of care to destroy AK, few advances have been made to the traditional approaches of physical ablation (e.g. cryosurgery, curettage) and chemotherapeutics (e.g. topical 5-fluorouracil).  The recent advances in photodynamic therapy (PDT) with 20% aminolevulinic acid (ALA) offer a novel, safe, and effective approach to AK therapy.  To evaluate the safety and efficacy of 20% ALA solution and blue light for the treatment of multiple facial AK.  A total of 32 patients were offered either partial treatment (i.e. individual target lesions treated) or confluent treatment (i.e. entire region treated).  At 15-20 hours after ALA solution application, treated areas were exposed to visible blue light for 16 minutes and 40 seconds.  ALA/PDT treatment resulted in a rapid resolution of multiple AK lesions with a limited period of associated photosensitivity.  Side effects experienced by individual patients were found to be influenced by a number of factors: use of analgesic and topical anesthetic agents, body region treated, partial versus confluent treatment, and light exposure time.  Twenty per cent ALA/PDT offers a safe, effective, and cost-efficient means of managing multiple AK lesions per treatment session with a low recurrence rate.  In addition to a favorable tolerability profile, most patients also achieved an improvement in skin texture.