You’ve spent a glorious day in your garden. Or you went on a beautiful hike. Or you picnicked with friends, or took your dog for a walk, or… well, whatever you did, you’re now itchy, splotchy and covered in little red bumps.
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Poison ivy strikes again — or maybe it’s poison oak or poison sumac, as all three plants contain the same oily, allergy-inducing sap called urushiol. An estimated 50% to 75% of the population is allergic to urushiol, which is found in every part of the plant, including the fruit, leaves, stem, and root.
“When the plant is broken, the resin leaks out,” explains dermatologist Pamela Ng, MD. “You’ll get this rash everywhere the resin touches — and then, if you get it on your hands and touch your face or other parts of your body, you’ll spread it.”
Dr. Ng talks about how to treat your poison ivy rash at home and what to expect as it heals.
How poison ivy rash develops
Poison ivy rash (along with the rash from poison oak and poison sumac) brings on bumps, blotches and, typically, a linear streak of swelling and blisters. “It can even be weeping and crusting,” Dr. Ng says, “and it’s intensely itchy.”
But the rash may not appear right away.
If you’ve been exposed to urushiol in the past and are re-exposed again, your rash will appear in four to 96 hours (though 24 to 48 hours is most common). But if it’s your first time being exposed to the plant, it can take up to two weeks for a rash to appear.
“Your immune system has to develop an allergic reaction first,” Dr. Ng says, “so if it’s the first time your body has ever seen it, it’s going to take a while for the rash to appear.”
Just how contagious is poison ivy?
Poison ivy rash is easily spread — on your body and even from pets to humans. If you touch a poison ivy plant with your hands, for example, and then touch your face or body, you’ll see a rash at both the original point of contact and the places you’ve touched.
And you don’t necessarily have to make contact with the plant itself in order to make contact with the resin. “People can break out after contact with the resin on their gardening tools, their clothing, or their dogs,” Dr. Ng says.
What to do if you’ve been exposed to poison ivy
Uh-oh. While working in the backyard, you pulled out some unwanted weeds before realizing that one of them was poison ivy. Now what?
If you know you’ve come into contact with poison ivy, poison oak or poison sumac, take a shower to wash off the resin. You won’t be able to get it all — after 10 minutes of washing your skin, only about 50% of the urushiol resin comes off — but you can lessen its impact.
You can also try Zanfel®, a special wash that you apply after exposure to limit urushiol’s effect on your skin. “It binds to the resin and neutralizes it so that it’s no longer an allergen for you,” Dr. Ng explains.
What to do if you have a poison ivy rash
Unfortunately, the best natural remedy for poison ivy is time.
“Poison ivy just has to run its own course,” Dr. Ng says. But if your rash has already developed, there are steps you can take to bring some relief in the meantime.
- Use cold compresses: Three to four times a day, cover the affected area with a damp towel for relief — but don’t get it too wet. You want your skin to feel cool, but it shouldn’t turn soft, moist and whitish (called “maceration”).
- Take a bath: Oatmeal baths and Domeboro® soaks are good home remedies for poison ivy itch, as they can relieve skin irritation. “They’re very soothing and can help dry up the rash,” Dr. Ng says.
- Take an oral antihistamine: Over-the-counter allergy medications such as Benadryl® (diphenhydramine) or Zyrtec® (cetirizine) can counter your allergic reaction to urushiol.
- Use an anti-itch product: Hydrocortisone creams, gels or ointments soothe the need to scratch. Just be sure not to use them for more than two weeks, and consult a doctor before using them around your eyes and/or using them on children. Calamine lotion and lotions containing menthol can help with itching, too.
- Avoid other topical treatments: Stay away from benzocaine and topical antihistamines, which don’t offer any additional benefit. Plus, using them can induce sensitization to some of the components of these creams, which increases your risk of developing an allergic reaction to them in the future.
- Protect your skin: Keep your rash clean to prevent infection, and if it’s blistered or weeping, wear long sleeves or a light bandage.
- Don’t touch: “Try your hardest not to pick or scratch,” Dr. Ng urges, “because once the skin is open, you’re susceptible to infection.” Clip your nails short and wear long sleeves to lessen the likelihood of scratching.
- Wait it out: If you’re wondering how long it takes for poison ivy to go away, you’ll have to be patient. The bumps and blisters can last 14 to 21 days.
Finally, don’t be alarmed if your rash gets worse before it gets better. It typically hits its peak at two weeks before starting to heal. “Try not to freak out if the rash isn’t gone yet,” Dr. Ng says. “This is its natural course.”
When to see a doctor
Most of the time, poison ivy heals on its own. But make an appointment with your doctor if you have:
- Severe, extensive and widespread rash.
- Rash on your face, including swelling around the eyelids.
- Rash accompanied by fever, chills or signs of infection.
Your doctor may put you on topical or oral steroid.
How to prevent poison ivy rash
Once you’ve had a rash from poison ivy, poison oak, or poison sumac, your symptoms will appear more quickly the next time you’re exposed.
To lower your risk, do the following when you’re outdoors, especially gardening or doing yard work:
- Apply an over-the-counter product designed to shield your skin from urushiol resin.
- Wear long-sleeved shirts, pants and thick, vinyl gloves, as the resin can penetrate thin, surgical-style gloves.
- Once indoors, take a shower to wash off urushiol resin and wash your clothes in detergent and hot water, including bleach, if appropriate, which can inactivate the resin.