& Joannie Dobbs Monday, May 16, 2005
How to avoid mango's itch
Mango season is near and while some people are eagerly watching their favorite fruit ripen on trees, others definitely are not itching for the fruit. This lack of enthusiasm -- or downright dread for some -- is due to "mango itch."
Question: What is mango itch?
Answer: This is the popular name for the allergic reaction some people experience when their skin is exposed to mango sap or the skins of the fruit.
An itchy rash develops and progresses into fluid-filled blisters that itch and ooze. Your dermatologist calls this an acute allergic contact dermatitis. Typically, symptoms develop several hours after exposure, build to a peak within two to five days, and clear up in about three weeks.
Q: Why does mango cause this skin irritation?
A: Some people are allergic to a chemical substance called urushiol -- a mixture of compounds found in the sap of the mango tree. Exposure occurs when handling freshly picked mangos that have juice dripping from the stem ends. The sappy juice gets on hands and, if not washed off quickly and adequately, can be spread to other body parts for up to three days.
Q: Are there other sources of urushiol?
A: Urushiol is the same toxin found in poison ivy and poison oak. People who have had reactions to these plants are very likely to have the same symptoms from exposure to mango sap. A classic 1968 article by Honolulu dermatologist Dr. Norman Goldstein lists the ginkgo, Japanese lacquer and rengas trees, pink peppercorns and cashew shell oil as other sources of urushiols.
Q: Can people who get mango itch eat mango?
A: Mango flesh has very low levels of urushiol, so most sensitive people can eat the fruit without problem as long as someone else peels it. The preparer should immediately and fully wash his or her hands, knife, knife handle and cutting board. The toxic sap can be picked up in a friendly touch or through contact with sap residue on a knife handle, furniture, or even by petting a dog that has been touched by someone with sap on their hands.
Q: What is the best way to prevent mango itch?
A: Carefully avoid exposure to other people, pets, garden tools, garments, etc., that may have been in contact with mango sap. Washing thoroughly with water or soap and water is generally adequate to eliminate the urushiol. Mango itchers also should wash off their bodies as soon as they suspect they have been exposed to mango sap. A product called IvyBlock can be spread on the skin to create a barrier between urushiol and the skin.
Q: Can you treat it?
A: The most effective over-the-counter product appears to be a medicinal soap called Zanfel. Serious symptoms require medical attention.
Prevention is always preferable, so make sure those around you know proper mango protocol.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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