The back, chest and shoulders can also be affected. One non-invasive and effective treatment is Blu-U Light therapy. A medication called Levulan(ALA) is applied to the skin and allowed to absorb into the tissue for approximately 60 minutes. The area is then exposed to the Blu-U Light for 15 to 20 minutes, which activates the medication. This process kills the acne causing bacteria. The treatment times may need to be adjusted according to skin type and response to the procedure. The side effects of this treatment are similar to sunburn. There may be redness, swelling and some discomfort. Cool compresses and vinegar/water soaks help soothe the treated skin. Exposure to daylight, which has a similar wavelength as the Blu-U Light, must be avoided for the next 24 to 48 hours. Daylight could cause the action of the medication to continue resulting in a stronger than desired response. Sunscreen with a high SPF must be worn the next 4 months to protect healed skin. Best results are achieved with a series of 3 to 4 treatments. Blu-U Light therapy is also an effective treatment for actinic keretoses (pre-cancerous lesions) that appear on the face, scalp, hands, arms, and some times legs and feet. Good results can occur after 1 to 3 treatments.