Did you know mangoes belong to the same plant family as poison ivy and that the skin of a mango can give you that same great contact dermatitis as if you played with poison ivy, poison oak, or poison sumac? If you have contact dermatitis from poison ivy or one of the other urushiol-containing plants (Toxicodendron species), exposure to the cut skin of a mango can be a highly unpleasant experience.

How Urushiol Causes Dermatitis

Urushiol is an oleoresin found in plant sap that protects the plant from injury. If the plant is damaged, the sap leaks to the surface where it reacts with oxygen in air to form a black-colored lacquer. Urushiol is actually the name of a group of related compounds. Each compound contains a catechol substituted with an alkyl chain. Whether an allergic reaction to the compound occurs and its severity is related to the degree of saturation of the alkyl chain. More saturated chains produce minimal to no reaction. If at least two double bonds are present in the chain, about 90% of the population suffers a reaction.

Urushiol is absorbed into skin or mucosa (e.g., mouth, eyes), where it reacts with Langerhan cells of the immune system. Urushiol acts as a hapten, causing a type IV hypersensitivity reaction, characterized by cytokine production and cytotoxic skin damage. This type of induced immune response is faster and stronger if a person has already been sensitized to it. It's possible to touch and eat mangoes without experiencing a problem for some time and then suffer a reaction upon a subsequent exposure.

How to Prevent Mango Contact Dermatitis

Obviously people eat mangoes all the time. The edible portion isn't likely to cause a problem. However, the vine of a mango contains sufficient urushiol to cause a reaction that rivals or exceeds that from poison ivy. The skin of the mango contains enough urushiol that if you are already sensitized to it, you will probably get contact dermatitis from exposure, usually on your hands, since most people don't bite into mangoes.

To prevent a reaction with mangoes, avoid handling them if you've ever had a reaction to poison ivy. Subsequent exposure in sensitive individuals worsens the reaction. If you live or vacation in an area where mango trees grow, avoid picking them or standing near the plant. Sap that may drip from the plant contains urushiol.

When shopping for mango at the store, use a plastic produce bag to pick up the fruit. At home, wear gloves or use the bag as protection to handle and peel the fruit. Mango skin is tough, so the safest route is to use a vegetable peeler. Otherwise a sharp knife will work. However, it's easier to simply cut a slice of mango, cut into the fruit, and bend the rind back "hedgehog" style. Because less peel is damaged, chemical exposure is minimized.

If you handle a mango, immediately wash your hands with soap and water. Washing removes the oily compound. However, within 10 minutes of exposure, about half the urushiol is absorbed into the skin. Absorbed urushiol cannot be removed by washing.

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