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Feed Your Face: How to Avoid "Lime" Disease

By Dr Jessica Wu

Do you make fresh lemonade? Do you squeeze fresh lemon on your fish? Do you enjoy fruity cocktails garnished with lime? If so, you may be at risk of developing an unsightly skin rash -- phytophotodermatitis (“phyto” refers to plants, “photo” to light, and “dermatitis” to skin inflammation). This is a common condition that can develop when you touch coumarins, natural plant compounds, and then spend time in the sun.


Coumarins are found in many plants, including limes, lemons, celery, parsley, fennel, dill, and figs. When skin that's come into contact with coumarins is exposed to the sun, a chemical reaction occurs that can lead to redness, swelling, and blistering -- very similar to sunburn -- that can sting, burn, or itch. Unlike a sunburn, however, the rash occurs only in spots that come into contact with the plant. Say you squeeze a fresh lemon and the juices from the fruit and oils from the rind drip or splatter onto your skin, or you touch your face with the hand that was squeezing the fruit -- if you happen to go out into the sun before you wash off the drips, the skin in these areas may turn red and even blister. After the blisters heal, the spots can turn brown and take months to fade. So the next time you make lemonade, mix cocktails, or prepare a meal with plants that contain coumarins, remember the following advice:

  • If you touch fruits and veggies that contain high levels of coumarins just before you go out in the sun, wash your hands first and don’t touch your face or other areas before you make it to the sink.
  • The rind of a fruit, rather than the juice, is more likely to cause this reaction. If you roll a lemon or lime in your hands to get it to release more juice, be sure to wash your hands before touching your face, even if you didn't touch the juice of the fruit.
  • UVA-blocking sunscreen may help prevent phytophotodermatitis because these are mainly the rays that react with the plant compounds. Your sunscreen should already have UVA protection, to fight sun damage.


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