Oh no, I've gotten into poison oak, poison ivy, or poison sumac. What do I do?
If you have brushed against poison oak, ivy, or sumac, wash the exposed skin with ordinary soap right away. Scratching does not spread the rash. A topical post based on recent experience, unfortunately. Poison ivy, poison oak, and poison sumac are common plants in the genus Toxicodendron, found throughout the United States, often near hiking trails. In the Bay Area the one you will actually meet is Pacific poison oak, Toxicodendron diversilobum, which is ubiquitous in California west of the Sierra Nevada; poison ivy is the eastern species and is not what grows on our trails. Roughly 50 to 75 percent of US adults are clinically sensitive to urushiol, the compound in the plant's sap that causes an itchy and painful allergic rash wherever it touches skin, and 10 to 15 percent never react at all.
The rash typically shows up within 8-72 hours after exposure, however, those who are highly allergic may show signs within 4 hours. The rash may continue to appear and spread for up to 21 days and will only appear in places where urushiol made contact. You cannot spread the rash by scratching or making contact with the blister fluid.
Common symptoms: Itching, red streaks or general redness, small bumps or raised patches of skin, blisters with or without fluid, blood blisters.
What to do if you think you have come into contact:
Step 1: As quickly as possible, wash your hands, under your fingernails, and the areas with regular soap or Tecnu if you have it. Speed is the whole game here: urushiol binds to skin within about half an hour, after which washing no longer removes it. Remove contaminated clothing and wash separately with hot water. Wipe down anything that may have come into contact with the urushiol, like shoes, camping gear, car seats, pets, or gardening tools.
Step 2: Schedule an appointment with your doctor. Mild cases may be treated at home with cold compresses, astringents, calamine lotion, and oral non-prescription antihistamines. Do not apply antihistamine creams or gels to the rash: topical antihistamines can worsen the rash and the itch, and topical diphenhydramine can itself cause an allergic skin reaction. Moderate to severe cases should be handled by a physician. If you have inhaled urushiol by burning poison oak, or if the rash is spreading into your eyes or genital areas, seek medical attention immediately.
Medical treatments for more serious cases can include stronger antihistamines, topical corticosteroids, and even oral corticosteroids. But steroids can have adverse effects so it's important to use them only under the close supervision of your doctor. Having a doctor on your team will help you determine if things are improving at a normal rate. Most importantly: do not panic.
