A Clinical Trial Evaluating the Role of Systemic Antihistamine Therapy in the Reduction of Adverse Effects Associated With Topical 5-aminolevulinic Acid Photodynamic Therapy

Inclusion criteria

• Age > 18
• Subjects with 5-20 actinic keratosis of the face
• Patients undergoing photodynamic therapy (PDT) to the face for AK with 5-aminolevulinic acid (ALA) activated by blue light.
• Must be willing to give and sign a HIPPA form, photo consent and informed consent form.
• Must be willing to comply with study dosing and complete the entire course of the study.
• Female patients will be either of non-childbearing potential defined as:

• Having no uterus
• No menses for at least 12 months.

Or;

(WOCBP) women of childbearing potential must agree to use an effective method of birth control during the course of the study, such as:

• Oral contraceptive pill, injection, implant, patch, vaginal ring, intrauterine device
• Intrauterine coil
• Bilateral tubal ligation
• Barrier method used with an additional form of contraception (e.g., sponge, spermicide or condom)
• Abstinence (If practicing abstinence must agree to use barrier method described above (d) if becomes sexually active).
• Vasectomized partner g. Negative urine pregnancy test results Baseline prior to study entry (if applicable)

Exclusion criteria

• Presence of incompletely healed wound in treatment area
• Presence of known or suspected BCC or SCC in treatment area
• Previous PDT or treatment of the face with any topical cytotoxic or immunomodulatory agent for AKs within the past 6 months
• Co-existing potentially confounding skin condition within treatment area (e.g. eczema, psoriasis, XP, rosacea) at investigator's discretion
• Presence of tattoo and/or scar in the treatment area that in the investigators opinion would interfere with study assessments
• Subjects with known photosensitivity or taking photosensitizing medications listed below:

• Oral diabetes medicines
• Griseofulvin
• Thiazide diuretics
• Sulfonylureas
• Phenothiazines
• Tetracycline's
• St. John's Wort
• Use of oral/topical retinoids within 1 month of Baseline
• Subjects with a history of sensitivity to porphyrins
• Subjects with recently excessive exposure of the treatment area to sunlight or artificial UV light (e.g.: use of tanning beds/booths and/or sunbathing) or expectations of tanning during the time of the study
• Female subjects who are pregnant, nursing an infant or planning a pregnancy during the study [throughout the course of the study
• Presence or evidence of any conditions that in the opinion of the investigator might impede the subject's ability to give consent or comply with protocol requirements.
• Current participation or participation within 30 days prior to the start of this study in a drug or other investigational research study
• History of non-compliance with clinical research protocols
• Ablative laser resurfacing to on their face within 12 months
• Non-ablative laser or light procedures to their face within the past 3 months
• Microdermabrasion (light or medium skin peel) treatment on their face within the past 30 days