Photoactive Porphyrins (PAP) Levels After Topical Visonac Application in Acne Patients

Inclusion Criteria: * Signed and verified informed consent form. For patients under age of 18, an assent form in conjunction with an informed consent form, signed and verified by parent/guardian. * Adolescent and adult female and male patients, from 12 to 35 years of age. * Patients with moderate to severe facial acne vulgaris according to the IGA scale. * Female patients who are surgically sterile, pre-menstrual, postmenopausal, abstinent, or willing to use an adequate means of contraception including birth control pills, or barrier methods and spermicide for at least 14 days prior to the study visit. * Patients with skin type II to III (Fitzpatrick). * Patients with 3 areas of 4 cm in diameter, each including at least with at least 4 inflammatory lesions (papules, pustules, and nodules) in the face (at cheek and forehead). Exclusion Criteria: * Subject is the investigator or any sub investigator, research assistant, pharmacist, study coordinator, other staff or relative thereof directly involved in the conduct of the protocol. * Patients unlikely to comply with the protocol, e.g. mental condition rendering the patient unable to understand the nature, scope, and possible consequences of the clinical study, uncooperative attitude or unlikelihood of completing the study (e.g. drug or alcohol abuse). * Female subjects with childbearing potential (i.e. ovulation, pre-menopausal, not surgically sterilized) not willing to use a medically accepted contraceptive regimen while on treatment. * Pregnancy * Lactating. * Participation in other clinical studies either currently or within the last 30 days. * Patients with porphyria. * Known allergy to (MAL), to a similar PDT compound, or to excipients of the cream * Patients with cutaneous photosensitivity. * Patients that have received topical treatments for their acne within the last 14 days. Medicated cleansers not containing active ingredients such as 5% BPO or high concentration of salicylic acid may be stopped before the treatment. (Cosmetic Cleansers that contains no more than 2 % salicylic acid is allowed). * Patients that has received oral antibiotics for treatment of their acne within the last month. * Patients that has received oral isotretinoin within the last 6 months. * Patients with a beard that might interfere with study assessments. * Patients with melanoma or dysplastic nevi in the treatment area