There are three related native American plants that can cause rashes:
The resin in the plants contains an oily substance called urushiol. Urushiol is easily transferred from the plants to other objects, including toys, clothing and animals. This chemical can remain active for a year or longer. It is important to know that the oils can also be transferred from clothing, pets and can be present in the smoke from a burning plant. Poison ivy/oak cannot be spread by contact with the rash.
These plants can cause an allergic reaction in nearly 85 percent of the population. They are found in different parts of the continent; poison ivy in the east and midwest and poison sumac in the west. To be allergic to these plants, your child must first be "sensitized" to the oils. This means that next time there is contact with the plant, a rash may occur.
The reaction is usually contact dermatitis, which may occur several hours, days, or even weeks after exposure. The dermatitis is characterized by a rash followed by bumps and blisters that itch. Sometimes, swelling occurs in the area of contact. Eventually, the blisters break, ooze and then crust over.
If contact with the plants has already occurred, you should remove the oils from the skin as soon as possible. Cleansing with an ordinary soap within six hours after the initial exposure has proven to be effective. Repeat the washing with the soap three times. There are also alcohol-based wipes that help remove the oils. Wash all clothes and shoes also, because the oils can remain on these.
If the blisters and rash are on the face, near the genitals, or all over the body, your child's physician should be notified. After a medical history and physical examination, your child's physician may prescribe a steroid cream, or systemic steroids, or steroid injections to help with the swelling and itching.
Bathing in an oatmeal bath product may reduce itching. The doctor may also prescribe medication by mouth for itching.
Here are some tips on preventing poison ivy and poison oak reactions: