Effects of Poison Oak on Human Skin

Close contact with poison oak can cause contact dermatitis if the person is sensitive to urushiol, the active ingredient in poison oak's resin. Poison ivy and poison sumac also contain urushiol, producing a similar reaction. Your best protection against poison oak it to avoid the plant by learning to identify it. Wear clothing that covers your skin when walking in the woods. Handle clothing that might have touched poison oak with gloves, and wash in soapy water.

Itching

• Moderate to severe itching might first alert you that you made contact with the plant. Scratching might spread the problem if you have urushiol under your nails. Wash your hands and the affected skin with warm soapy water. "Taber's Cyclopedic Medical Dictionary" recommends bathing the effected area in water as warm as you can stand it for one to two minutes while you massage the skin for itch relief.

Rash

• The rash can appear on the skin within several hours to several days of exposure, according to "Taber's." The rash might appear in a straight line where you made contact with the plant. If you brushed up against a pet or clothing that made contact with urushiol, the rash can appear more spread out on the skin.

Redness and Swelling

• The allergic reaction to urushiol causes the skin to become inflamed and red. Continued inflammation might cause the skin to become swollen.

Blisters

• After the skin begins to itch, small blisters can break out over your skin's surface. The blisters might burst, especially if they are scratched. The serum in the blister might ooze and spread over the skin before crusting. The fluid from the blister will not spread the rash, although other less sensitive areas might break out over time and make it appear to do so. Your symptoms can last several weeks.

  Scratching the blisters can, however, cause infection, leading to a fever and possible pus in the blisters. Seek medical attention if the symptoms are severe or if infection occurs.