Sunburn: Prevention

Everyone from age six months on should use a water-resistant sunscreen with a sun protective factor (SPF) of at least 15. Apply at least an ounce 15–30 minutes before going outside. It should be reapplied every two hours (more often after swimming). Babies should be kept completely out of the sun for the first six months of life, because their skin is thinner than older children. Sunscreens have not been approved for infants.

In addition, people should:

• limit sun exposure to 15 minutes the first day, even if the weather is hazy, slowly increasing exposure daily
• reapply sunscreen every two hours (more often if sweating or swimming)
• reapply waterproof sunscreen after swimming more than 80 minutes, after toweling off, or after perspiring heavily
• avoid the sun between 10 A.M. and 3 P.M
• use waterproof sunscreen on legs and feet, since the sun can burn even through water
• wear an opaque shirt in water, because reflected rays are intensified

If using a sunscreen under SPF 15, simply applying more of the same SPF won't prolong allowed time in the sun. Instead, patients should use a higher SPF in order to lengthen exposure safely. A billed cap protects 70% of the face; a wide-brimmed hat is better. People at very high risk for skin cancer can wear clothing that blocks almost all UV rays, but most people can simply wear white cotton summer-weight clothing with a tight weave.

— Carol A. Turkington