Poison ivy, oak, or sumac poisoning is an allergic reaction that results from touching the sap of these plants. The sap may be on the plant, in the ashes of burned plants, on an animal, or on other objects that came in contact with the plant, such as clothing, garden tools, and sports equipment.

Small amounts of sap can remain under a person's fingernails for several days unless it is deliberately removed with very good cleaning.

One poisonous ingredient is the chemical urushiol.

• Bruised roots, stems, flowers, leaves, fruit
• Pollen of poison ivy, poison oak, and poison sumac

• Blisters
• Burning skin
• Itching
• Redness of the skin
• Swelling

Wash the area immediately with soap and water. Quickly washing the area can prevent a reaction, but it doesn't usually help if done more than 1 hour after touching the plant's sap.

Carefully wash any contaminated objects or clothing alone in hot soapy water. Do not let the items touch any other clothing or materials.

An over-the-counter antihistamine such as Benadryl or a steroid cream may help relieve itching.

Determine the following information:

• The patient's age, weight, and condition
• The name of the plant
• The amount swallowed (if swallowed)

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container with you to the hospital, if possible.

See: Poison control center - emergency number

Unless the reaction is severe, you will probably not need to visit the emergency room. If you are concerned, call your doctor or poison control.

At the doctor's office, you may receive:

• Antihistamine or steroids by mouth or applied to the skin
• Washing of the skin (irrigation)

Life-threatening reactions may occur if the poisonous ingredients are swallowed or are breathed in (which can happen when the plants are burned).

Typical skin rashes usually go away without any long-term problems. A skin infection may develop if the affected areas are not kept clean.

Auerbach PS. Wilderness Medicine. 4th ed. St. Louis, Mo: Mosby; 2001: 194-195.