People with photosensitivity have an immunological response to light, usually sunlight. They typically break out in a rash when exposed to sunlight; how much exposure it takes to cause a reaction varies from person to person. Several conditions, such as erythropoietic protoporphyria and polymorphous light eruption, share the common symptom of hypersensitivity to light—also typically sunlight.
People taking certain prescription drugs (sulfonamides, tetracycline, and thiazide diuretics) or herbs (St. John’s wort, for example) and those with systemic lupus erythematosus have increased susceptibility to adverse effects from sun exposure.
What are the symptoms of photosensitivity?
Symptoms may include a pink or red skin rash with blotchy blisters, scaly patches, or raised spots on areas directly exposed to the sun. The affected area may itch or burn, and the rash may last for several days. In some people, the reaction to sunlight gradually becomes less with subsequent exposures.
Dietary changes that may be helpful for photosensitivity
One of the conditions that may trigger photosensitivity—porphyria cutanea tarda—has been linked to alcohol consumption.1 People with this form of porphyria should avoid alcohol. Some people have been reported to develop a photosensitivity reaction to the artificial sweetener, saccharin.2
Lifestyle changes that may be helpful for photosensitivity
People with photosensitivity need to protect themselves from the sun by using sunscreen, wearing protective clothing (such as long-sleeved shirts), and avoiding excess exposure to the sun.
Nutritional supplements that may be helpful for photosensitivity
Years ago, researchers theorized that beta-carotene in skin might help protect against sensitivity to ultraviolet light from the sun. Large amounts of beta-carotene (up to 300,000 IU per day for at least several months) have allowed people with photosensitivity to stay out in the sun several times longer than they otherwise could tolerate.3 4 5 The protective effect appears to result from beta-carotene’s ability to protect against free-radical damage caused by sunlight.6
Adenosine monophosphate (AMP) is a substance made in the body that is also distributed as a supplement, although it is not widely available. According to one report, 90% of people with porphyria cutanea tarda responded well to 160 to 200 mg of AMP per day taken for at least one month.7 Complete alleviation of photosensitivity occurred in about half of the people who took AMP.
In a small preliminary trial, supplementation with fish oil (10 grams per day for three months) reduced photosensitivity in 90% of people suffering from polymorphous light eruptions.8
Less is known about the effects of supplementation with other antioxidants on photosensitivity. Research with vitamin E has been limited and has not yielded consistent results.9 10
Cases have been reported of people with photosensitivity who responded to vitamin B6 supplementation.11 12 Amounts of vitamin B6 used to successfully reduce reactions to sunlight have varied considerably. Some doctors suggest a trial of 100 to 200 mg per day for three months. People wishing to take more than 200 mg of vitamin B6 per day should do so only under medical supervision.
Niacinamide, a form of vitamin B3, can reduce the formation of a kynurenic acid—a substance that has been linked to photosensitivity. One trial studied the effects of niacinamide in people who had polymorphous light eruption.13 While taking one gram three times per day, most people remained free of problems, despite exposure to the sun. Because of the potential for adverse effects, people taking this much niacinamide should do so only under medical supervision.
Are there any side effects or interactions with photosensitivity?
Refer to the individual supplement for information about any side effects or interactions.