Phototoxicity

Phototoxicity is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity. The skin response resembles an exaggerated sunburn. The involved chemical may enter into the skin by topical administration or it may reach the skin via systemic circulation following ingestion or parenteral administration. The chemical needs to be "photoactivated" by light in the UVA spectrum. The mechanism of action varies — the chemical may become excited by light and directly damage surrounding tissue, or it may lead to the formation of free radicals that damage tissue indirectly.

Causes[edit | edit source]

Phototoxicity can be caused by various agents:

Certain medications, such as tetracycline, sulphonamides, quinolones, phenothiazines, and psoralens
Certain essential oils, such as bergamot, lime, lemon, grapefruit, cedar, and fig
Certain plants, such as giant hogweed, wild parsnip, lemon verbena, and St John's wort
Certain chemicals, such as furocoumarins, coumarins, and xanthotoxin

Symptoms[edit | edit source]

Symptoms of phototoxicity can include:

Redness (similar to sunburn)
Swelling
Itching
Burning
Blisters and scaling
Hyperpigmentation (dark patches on the skin)

Treatment[edit | edit source]

Treatment for phototoxicity is similar to the treatment for a severe sunburn. This can include:

Cold compresses
Over-the-counter hydrocortisone creams
Non-prescription pain relievers
Stay out of the sun as much as possible until the skin has healed

Prevention[edit | edit source]

Prevention of phototoxicity involves avoiding known triggers, such as certain medications, plants, and chemicals. If exposure cannot be avoided, protective clothing and sunscreens may help prevent a reaction.

See also[edit | edit source]

Phototoxicity Resources
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