
What is a photosensitivity reaction?
"Photo" refers to light. A photosensitivity reaction is a disorder in which your immune system overreacts to sunlight. This reaction is sometimes also called a sun allergy.
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Photosensitivity causes red, itchy patches on your skin, usually skin that has been in sunlight
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Certain medicines or chemicals can make your skin sensitive to the sun
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Photosensitivity reactions can run in families
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Some diseases can cause a severe photosensitivity reaction
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Photosensitivity reactions go away on their own, but medicine sometimes helps you feel better
What causes photosensitivity reactions?
There are different types of photosensitivity reactions that have different causes, including:
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Those caused by certain medicines you take
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Those caused by certain chemicals you were exposed to
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Those caused by diseases you have (such as lupus)
At least 100 medicines and chemicals are known to cause photosensitivity.
Sometimes there doesn't seem to be a particular cause, although photosensitivity sometimes runs in families.