These are among a host of plants (many found in the refrigerator vegetable drawer) that produce chemicals that will kill skin cells when activated by sunlight. The result can be a serious, localized sunburn — sometimes with blistering.
Summer is the time for outdoor fun. But to enjoy it safely, people should heed some general warnings. Check for ticks. Head indoors at the first sign of lightning. Slather on sunscreen. And if you put up a lemonade stand, squeeze those lemons indoors. Then wash your hands well — at least if you’ll be out in the sun. The reason: Lemons make chemicals that harm the skin.
In the presence of sunlight, these chemicals can lead to painful burns or rashes. Each year, many people — children and adults alike — learn this the hard way. Their burns sometimes will be severe enough to blister. Ouch!
Robin Gehris is a skin specialist in Pennsylvania at Children’s Hospital of Pittsburgh. In summer, she sees these burns in her young patients “at least once a week.” Most cases have been triggered by limes and lemons, she says.
One reasonable explanation: lemonade stands.
The ancient Egyptians first described this special type of sunburn more than 3,000 years ago in the Ebers Papyrus. It’s one of the oldest and most important medical documents (written, yes, on papyrus). Four California doctors wrote about it in a 2016 review paper on this special class of sunburns.
These burns also have a special name: phytophotodermatitis (FY-toh-der-muh-TY-tis). It simply means some plant-based thing has made the skin super-sensitive to sunlight. The topic hits the news every so often. And it just did again in the United States as biologists reported in mid-June that they had discovered giant hogweeds for the first time in Virginia. Former homeowners had planted them in their yard because they liked the plants' exotic look.
Bad idea.
The plants look like Queen Anne’s lace on steroids. The “giant” part of their name makes sense. This relative of the carrot can grow to heights of 4.3 meters (14 feet). And this plant makes the same class of toxic compounds as lemons. That’s why biologists tend to approach hogweeds wearing hazmat suits to avoid the chemicals that can cause burns (or, potentially, blindness — although that has not been reported thus far).
This giant hogweed contains chemicals that make the skin especially likely to become sunburned. Other plants in the same family include celery, carrots, parsnip, dill and fennel. CREDIT: SALICYNA/WIKIMEDIA COMMONS (CC BY-SA 4.0)
Jordan Metzgar, curator of Virginia Tech’s Massey Herbarium, describes confirming the first known infestation of giant hogweed in his state in 2018 CREDIT: Virginia Tech
