Also indexed as: Light Sensitivity
People with photosensitivity 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—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.
Checklist for
Photosensitivity
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.
How is it treated? Conventional treatment includes the
avoidance of direct sunlight and the use of sunscreen. In addition, doctors may prescribe beta-carotene or hydroxychloroquine to reduce the severity of reactions.
Oral corticosteroids are often prescribed to
clear up the skin rash once it has appeared. In some cases, psoralen plus ultraviolet therapy
(PUVA) is administered over the course of several weeks to prevent photosensitivity. In
addition, the avoidance of medications and products known to cause photosensitivity may be
recommended.
Dietary changes that may be helpful: 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: 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: 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? Refer to the individual supplement for
information about any side effects or interactions.
References:
1. Cripps DJ. Diet and alcohol effects on the manifestation of hepatic
porphyrias. Fed Proc 1987;46:1894–900.
2. Gordon HH. Photosensitivity to saccharin. J Am Acad Dermatol
1983;8:565 [letter].
3. Mathews-Roth MM, Pathak MA, Fitzpatrick TB, et al. Beta-carotene as an
oral photoprotective agent in erythropoietic protoporphyria. JAMA
1974;228:1004–8.
4. Nordlund JJ, Klaus SN, Mathews-Roth MM, Pathak MA. New therapy for
polymorphous light eruption. Arch Dermatol 1973;108:710–2.
5. Mathews-Roth MM, Pathak MA, Fitzpatrick TB, et al. Beta-carotene as a
photoprotective agent in erythropoietic protoporphyria. N Engl J Med
1970;282:1231–4.
6. Mathews-Roth MM. Photoprotection by carotenoids. Fed Proc
1987;46:1890–3 [review].
7. Gajdos A. AMP in porphyria cutanea tarda. Lancet 1974;I:163
[letter].
8. Rhodes LE, Durham BH, Fraser WD, Friedmann PS. Dietary fish oil
reduces basal and ultraviolet B-generated PGE2 levels in skin and increases the threshold to
provocation of polymorphic light eruption. J Invest Dermatol
1995;105:532–5.
9. Ayres S Jr, Mihan R. Porphyrea cutanea tarda: response to vitamin E.
Cutis 1978;22:50.
10. Werninghaus K, Meydani M, Bhawan J, et al. Evaluation of the
photoprotective effect of oral vitamin E supplementation. Arch Dermatol
1994;130:1257–61.
11. Kaufman G. Pyridoxine against amiodarone-induced photosensitivity.
Lancet 1984;i:51–2 [letter].
12. Ross JB, Moss MA. Relief of the photosensitivity of erythropoietic
protoporphyria by pyridoxine. J Am Acad Dermatol 1990;22:340–2.
13. Neumann R, Rappold E, Pohl-Markl H. Treatment of polymorphous light
eruption with nicotinamide: a pilot study. Br J Dermatol 1986;115:77–80.
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purposes only. It is based on scientific studies (human, animal, or in vitro),
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