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What is a photosensitivity reaction?

What causes photosensitivity reactions?

What are the symptoms of a photosensitivity reaction?

How do doctors tell if I have a photosensitivity reaction?

How do doctors treat photosensitivity reactions?

Sunlight and Skin Damage

Photosensitivity Reactions

Sunburn

ADDITIONAL CONTENT

Radiopaque contrast agents are used during x-rays and CT scans to distinguish one structure from another or to provide greater detail. A radiopaque contrast agent that contains which of the following substances is most appropriate to use for evaluating blood vessels?

Barium
Gadolinium
Iodine
Microbubbles

Photosensitivity Reactions

By

The Manual's Editorial Staff

Last full review/revision Feb 2020| Content last modified Feb 2020

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"Photo" refers to light. A photosensitivity reaction is a disorder in which your immune system Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more overreacts to sunlight. This reaction is sometimes also called a sun allergy.

Photosensitivity causes red, itchy patches on your skin, usually skin that has been in sunlight
Certain medicines or chemicals can make your skin sensitive to the sun
Photosensitivity reactions can run in families
Some diseases can cause a severe photosensitivity reaction
Photosensitivity reactions go away on their own, but medicine sometimes helps you feel better

There are different types of photosensitivity reactions that have different causes, including:

Those caused by certain medicines you take
Those caused by certain chemicals you were exposed to
Those caused by diseases you have (such as lupus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more )

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.

Symptoms are different depending on the type of photosensitivity reaction you have. You may have:

Itchy, red swellings or bumps
Painful, red patches like sunburn

Symptoms usually appear only on skin that was exposed to the sun. But one kind of photosensitivity reaction can spread to skin that wasn't exposed to sun.

Doctors suspect a photosensitivity reaction when you have a rash mostly on areas of your skin exposed to the sun. Doctors will ask you about medicines and substances you take or apply to your skin.

Doctors may do tests, such as:

Skin patch tests to see what substances you may be allergic to
Shining a UV light on your skin to see if it causes the reaction

Your treatment depends on which type of photosensitivity reaction you have.

Doctors will:

Tell you to stop using any medicines or substances that cause photosensitivity
Give you corticosteroids to apply to your skin or take by mouth
Give you other medicines if the reactions are frequent or severe

Doctors may also have you:

Avoid spending too much time in sunlight
Wear protective clothing when you go outside

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Folliculitis and Skin Abscesses

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Sunburn

Sunlight and Skin Damage

Photosensitivity Reactions

Sunburn

Photosensitivity Reactions

Physical Allergy

Drug Rashes

Radiopaque contrast agents are used during x-rays and CT scans to distinguish one structure from another or to provide greater detail. A radiopaque contrast agent that contains which of the following substances is most appropriate to use for evaluating blood vessels?

Barium
Gadolinium
Iodine
Microbubbles

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