Common side effects of PDT include redness, swelling, itching, and even small blisters. The treated area of the skin is usually quite red and may appear to be flaking or peeling, as it would after a mild sunburn. The redness, and perhaps some of the flaking, can last for several days to a week or even two weeks. Other possible side effects of PDT include swelling at or near the area of skin treated, discoloration of your skin, scales, crusts or blisters on your skin receiving treatment, itching, stinging or burning, and skin infections. Damage to normal cells is limited. One of the most common side effects of PDT is sensitivity to bright lights and sunlight. These reactions caused by PDT light can show up on the skin where the drug is applied. They usually involve redness and a tingling or burning sensation. Additionally, some of the side effects of PDT depend on the area that is treated. For example, if PDT is used to treat esophageal cancer, side effects may include hiccups, difficulty swallowing, and nausea and vomiting.