Can Limes Burn Your Skin?

Learn about the other “lime disease.”

Written by

Melissa Petruzzello

Fact-checked by

Britannica Editors

History

Not to make you scared of your favorite zesty citrus fruit, but yes, limes can burn you. Under the right conditions, contact with lime juice followed by exposure to sunlight can trigger a reaction called phytophotodermatitis—phyto meaning “plant,” photo meaning “light,” and dermatitis meaning “skin inflammation.” The condition is caused by a class of plant chemicals known as furocoumarins (also called furanocoumarins), which are found in limes and a surprising number of other plants.

Furocoumarins interfere with the skin’s ability to manage ultraviolet (UV) light exposure but are not themselves particularly harmful in moderate doses. However, if lime juice gets on your skin and you head out into the sun, the UV radiation activates the chemicals. Within hours—or sometimes a day or two later—you can develop redness, swelling, and painful, itchy blisters that resemble severe sunburn or rash. In more severe cases the damage can approach second-degree burns and may leave lingering dark patches of skin (post-inflammatory hyperpigmentation) that can last for weeks or months. Because the reaction depends on both plant chemicals and light, it often appears in streaks or drip-shaped patterns that trace where the juice splashed or ran. Dermatologists sometimes call these injuries “margarita burns” or, punningly, “lime disease.”

Such burns are not uncommon, though you generally need a decent amount of juice on your skin, plus strong UV exposure—think bartending outdoors or making ceviche on the beach. In everyday use washing up well before heading outside can eliminate the risk.

It’s not just limes

Giant hogweedFlowers of giant hogweed (*Heracleum mantegazzianum*). Contact with the sap can cause phytophotodermatitis, in which the skin severely blisters if exposed to the sun, and can result in blindness if the sap enters the eyes.

Limes are far from unique in this ability. Many members of the carrot family (Apiaceae) can trigger this reaction, the most notorious species being giant hogweed (Heracleum mantegazzianum). Originally from Eurasia but now also found in parts of North America, the entire plant is considered toxic and contains especially potent concentrations of furocoumarins in its sap. Contact followed by sunlight can result in severe blistering, scarring, and—if the sap reaches the eyes—temporary or even permanent vision damage. Tragically, its victims are often children playing outside who unwittingly run through patches of the towering weed. Compared with hogweed injuries, lime burns are typically milder, though they can still be painful and visually dramatic.

Other Plants That Can Cause Phytophotodermatitis

Why do plants make these chemicals?

Plants produce an astounding array of secondary metabolites, which are chemicals that are not directly involved in growth or reproduction. Many serve defensive functions, an important strategy since plants, as sessile (nonmoving) organisms, have little other recourse against herbivores, UV radiation, and diseases. Furocoumarins can deter an herbivore by damaging the animal’s tissues and making the plant less palatable. They also appear to have antifungal and antibacterial properties and may help protect plant tissues from infection. As defense mechanisms go, light-activated toxicity is remarkably effective.

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