When the long school year ended, I always looked forward to a relaxing vacation with my parents in Florida. But one year, upon arrival, I was shocked to find my dad’s face covered in a red, blistered rash. Based on the appearance and his symptoms, I immediately suspected poison ivy.

However, after thoroughly searching the property, we found no trace of it anywhere around our home. Since he had a wide variety of plants and fruit trees in his yard, we began investigating whether one of them might be the cause. The newest addition to his garden was a mango tree, so that’s where we started.

Mangoes are a tropical fruit that grow on trees in warm locations. According to the Texas A&M Extension website, mangoes are regarded as the queen of fruits in tropical areas of the world.

Generally, mangoes are enjoyed fresh or in desserts and juices, but they have a darker side for some unlucky individuals.

Mangoes are a part of the Anacardiaceae family that also includes such well-known but not so well-liked members including poison ivy, poison oak and poison sumac. Some other surprising members are cashew trees, pistachio trees and the Lacquer tree. So what do all these plants have in common? They all contain a toxic oil called urushiol.

Urushiol is found in all parts of the plant including leaves, roots, stems and even berries in the group of poison ivy, poison oak and poison sumac plants. It is responsible for the itchy and irritating rash experienced by many people who come in contact with this oil. The mango and cashew have high concentrations of urushiol in the tree bark, sap and skin of the fruit. People who chew the mango flesh directly from the skin frequently can get a blistering rash on their lips. The shell of raw cashews contains this oil, but commercially sold cashews are processed through roasting with special equipment to remove the oils.

Urushiol is not an irritant that burns your skin, but the rash is a result of your own immune system attacking your skin cells. Depending on one’s sensitivity, the rash can appear anywhere from a few hours to a couple days or longer. If you have a sensitivity or feel you have been in close contact with this oil, the best prevention of further spreading is to immediately wash exposed areas with soap and cool water. In addition, it is important to wash the clothes you were wearing in hot, soapy water, handling them carefully so as not to spread the oil any further.

As for my dad, he delegated the mango picking and peeling to my mom and me, but he never stopped enjoying them.

Dubois is an Ohio State University Extension Master Gardener Volunteer in Mahoning County.