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Taipei City Hospital


Skin protection in the summer

         Summer is the time for sun protection products. The sun protection factor (SPF) value labelled on sunscreens represents their ability to prevent the ultraviolet B (UVB) rays of ultraviolet light. Under the same light intensity, if the skin reddens after one-minute exposure, sunscreens with SPF 20 will delay the skin redness for 20 minutes. In theory, the products with SPF 10, SPF 30 and SPF 50 can block 90%, 96.7% and 98% of UVB, respectively. The premise is to have sufficient sunscreen applied.
       “According to the standard set by the U.S. Food and Drug Administration (FDA), SPF is the value measured by applying the sunscreen product at 2 milligrams per square centimeter (mg/cm2). If the amount of the sunscreen product applied is insufficient, the effectiveness of sunscreen protection cannot be reached as labelled,” said Dr. Kang-Ling Liu, a dermatologist at Taipei City Hospital Renai Branch. “In general, the size of an individual’s palm can be a good reference. A knuckle-sized amount of sunscreen can be applied to the approximate area of both palms. For example, the area of the face (including the forehead) is about the area of three to four palms, for which it is recommended that the amount of sunscreen applied should be about the size of two knuckles.”
       Dr. Liu stated that if proper skin protection measures are not taken, in addition to tanning and sunburn, it can easily result in dermatoheliosis, solar lentigo, actinic keratosis and squamous cell carcinoma in the long term. As prevention is better than a cure, it is urged that people should be aware of skin protection in the summer to prevent skin lesions as a result of sunlight.