Photoreactive products can also aggravate existing skin problems like eczema, herpes, psoriasis and acne, and can inflame scar tissue. They can also precipitate or worsen autoimmune diseases, such as lupus erythematosus and rheumatoid arthritis, in which the body's immune system mistakenly destroys itself. The answer is not clear. Sunscreens do lessen the effects of UV radiation, but some contain ingredients that themselves may cause photosensitivity in some people. Sunscreens containing bergamot oil, sandalwood oil, benzophenones, PABA, cinnamates, salicylates, anthranilates, PSBA, mexenone, and oxybenzone can all cause photosensitivity reactions.
Titanium dioxide is the least likely sunscreen to cause photosensitivity disorders.
Before going out in the sun, it's a good idea to check with your doctor to see if any of the medications you're taking is likely to cause problems and decide how to best avoid such reactions. Read the labels of OTC drugs and note if they may be photosensitizing. If you get symptoms after being out in the sun, you may want to consider what drugs and chemicals you are using and contact your doctor immediately for advice. Conn. Tanning Booths Bigger Problem Tanning booths and the use of indoor tanning products can be more of a problem than natural sunlight, and this is true with photosensitivity reactions as well as in general. This information must appear on the product's warning label and is no way to be considered as a safe limit.