Short-incubation Levulan Photodynamic Therapy Versus Vehicle for Face/Scalp Actinic Keratosis (AK)

Inclusion Criteria:

* 6-20 Grade 1/2 AKs on the face or scalp
* a history of AK therapy within the treatment area at least twice in the two years prior to study entry

Exclusion Criteria:

* Pregnancy
* Grade 3 AKs or atypical AKs (e.g., AK \> 1 cm2 in size) within the Treatment Area
* lesions suspicious for skin cancer (skin cancer not ruled out by biopsy) or untreated skin cancers within the Treatment Area
* plans to be exposed to artificial tanning devices or excessive sunlight during the trial
* Subject is immunosuppressed
* unsuccessful outcome from previous ALA-PDT therapy
* history of cutaneous photosensitization, porphyria, hypersensitivity to porphyrins or photodermatosis
* skin pathology or condition which could interfere with the evaluation of the test product or requires the use of interfering topical or systemic therapy
* skin pathology or condition that could interfere with the evaluation of the test product or requires the use of interfering topical or systemic therapy
* any condition which would make it unsafe for the subject to participate in this research study
* currently enrolled in an investigational drug or device study
* has received an investigational drug or been treated with an investigational device within 30 days prior to the initiation of treatment
* known sensitivity to one or more of the vehicle components (ethyl alcohol, isopropyl alcohol, laureth 4, polyethylene glycol)
* Subject has;

  * an active herpes simplex infection OR
  * a history of 2 or more outbreaks within the past 12 months, in the Treatment Area
* use of the following topical preparations on the extremities to be treated:

  * Keratolytics including urea (greater than 5%), alpha hydroxyacids \[e.g.glycolic acid, lactic acid, etc. greater than 5%\], salicylic acid (greater than 2%) within 2 days of initiation of treatment.
  * Cryotherapy within 2 weeks of initiation of treatment
  * Retinoids, including tazarotene, adapalene, tretinoin, retinol, within 4 weeks of initiation of treatment.
  * Microdermabrasion, laser ablative treatments, ALA-PDT, chemical peels, 5-FU, diclofenac, imiquimod or other topical treatments for AK within 8 weeks of initiation of treatment.
  * Two or more ALA PDT treatments in the past 6 months
* use of systemic retinoid therapy within 6 months of initiation of treatment.