The summer’s here and for many that means spending time outdoors and enjoying the summer sun. Of course, protecting your skin from the sun’s damaging rays is important to prevent a painful sunburn and reduce the risk of skin cancer in the future. Sunblock and sunscreen are essential to a safe summer.
For some, however, sunscreen can cause red, swollen itchy bumps that can last several days after use. Ironically, in some cases the rash only occurs when the sunscreen is applied and then person goes out in the sun. This is known as photo-allergic reaction or photo-contact dermatitis. Contact dermatitis is a delayed allergic skin reaction caused by many different chemical and natural substances, the best known being poison ivy. In photo-contact dermatitis, the combination of the chemical plus sun exposure triggers the reaction. A number of ingredients found in sunscreens – oxybenzone, benzophenones, cinnamates, and dibenzoylmethanes – can triggers this reaction.
Discovering what triggers contact dermatitis is achieved through a detailed history and use of patch tests. Patch tests are an allergy test in which suspected individual chemical triggers are applied to the skin on specialized adhesive patches. The patches are left in place for 48 hours or so and then examined for areas or irritation. Patch testing can be extremely helpful in figuring out the cause(s) of chronic rashes. The diagnosis of photo-contact dermatitis, however, is a bit more complicated as testing requires not only the suspected chemical, but also exposure to certain wavelengths of light. This is called photopatch testing.
What should you do if you have developed sunscreen allergy?
First, consider using sunscreens that are based on zinc oxide or titanium dioxide, that are fragrance free and PABA free. Also, wear a hat and cover up when out in the sun. Finally, consult your trusted Allergy Partners allergist if you or a family member is suffering from sunscreen allergy or other suspected contact allergic rashes.
Dr. William McCann
Allergy Partners of Western North Carolina