Levulan Pdt Treatment How Long Do You Have to Stay out of the Sun?

Levulan is active on your skin for 48 hours after application.  You need to stay out of the sun (or any other bright light source) for 48 hours, or you can get a burn.  You will actually feel tingling, burning, or warmth, and this is an indication that the medication is being activated.  

PDT, or photodynamic therapy, is FDA approved to treat actinic keratosis, or pre-cancerous lesions caused by the sun.  It's also used (off-label) to treat acne.  Typically, Levulan is applied to the face one hour prior to the treatment.  The patient then sits under the blue light (in the office) for an amount of time, usually about 16 minutes.  Areas that are damaged and have pre-cancerous changes become red and crusted, and heal after 1-2 weeks.  It is advised that the patient stay out of the sun for 48-72 hours following the treatment, because levulan makes skin very sensitive to sunlight.