What Is Rhus Dermatitis?

An allergic contact dermatitis caused by exposure to plants of the genus Toxicodendron (formerly Rhus). These include poison ivy, poison oak, and poison sumac, all plants that contain the substance urushiol, a potent skin sensitizing agent. (

What causes Rhus dermatitis?

Rhus dermatitis can be caused by poison ivy, poison sumac, or poison oak. The oil on the leaves, roots, and stems contains urushiol, a highly allergenic compound that can cause a type IV hypersensitivity reaction. Allergic persons are sensitized to the compound before reacting to the oil.

Is Rhus dermatitis contagious?

There's no way to desensitize people allergic to Rhus plants. Dogs and other animals are not affected by poison ivy, but people can get the rash by petting a dog that's been exposed. The rash itself is not contagious, and the fluid in the blisters does not spread the rash.