Everyone's reaction to poison ivy is different - here's how to tell how long your rash will last

• A poison ivy rash will last at least a week and likely more if you've never been exposed before.
• If you come into contact with poison ivy, the rash will typically appear within 12-48 hours.
• In order to reduce the severity of your rash, wash the site of contact immediately after exposure.

According to the American Academy of Dermatology, a poison ivy rash might last three weeks or more if you've never experienced it before. Otherwise, it may take two weeks or less before the rash goes away on its own.

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However, rash duration and severity also depend on how badly you were exposed in the first place.

For example, minimal exposure may have limited symptoms and resolve in less time, says John Jelesko, PhD, associate professor in the School of Plant and Environmental Sciences at the Virginia Polytechnic Institute and State University.

You can let a mild rash run its course, but severe cases may require oral corticosteroids to reduce the rash duration. Here's how you can identify, treat, and prevent poison ivy rashes.

What is a poison ivy rash?

Poison ivy, poison oak, and sumac all produce urushiol, an oily sap that causes an allergic reaction upon contact with the skin.

You may develop a rash in about 12 to 48 hours if you touch any of these plants or anything that came into contact with them, such as unwashed clothing, pet fur, or gardening tools.

While symptoms generally differ from one individual to another, common signs of a poison ivy rash show up at the point of contact and include:

• Intense and persistent itchiness that can wake you up from sleep
• Red, swollen bumps that may grow in size
• Blisters that may ooze clear, watery fluid and eventually crust over

In rare cases, some people develop black spots or streaks instead of a reddish rash.

"Poison ivy is not contagious. However, the part of poison ivy that causes allergic reactions [aka urushiol] can be spread on our skin or clothing, so it is important to rinse the skin well after contact with poison ivy and to wash clothing thoroughly," says Jeffrey Cohen, MD, a dermatologist at Yale Medicine and assistant professor of dermatology at the Yale School of Medicine.

How to treat a poison ivy rash

If you've been exposed to urushiol either from poison ivy, or another plant, you can do the following:

• Wash your skin immediately: Wash your skin with copious amounts of soap and water as soon as possible. According to Jelesko, washing within 15 minutes of initial contact can be effective in preventing and/or minimizing poison ivy rash symptoms later on.
• Let it run its course: "Once the rash symptoms begin, the treatment options become very limited," Jelesko says. A poison ivy rash will eventually go away on its own in about two to three weeks.
• Take prescription steroid medications: For severe cases, "oral steroid treatment is the gold standard for reducing and stopping and reversing poison ivy rash symptoms," says Jelesko. "This is a decision that needs to be made in conjunction with your physician."

It's important to note that, "there are over-the-counter products marketed for reducing poison ivy rash symptoms, but the effectiveness of these are rarely supported by well-controlled clinical trials," Jelesko says.

Therefore, it's best to refrain from using any topical lotions or creams without consulting your doctor first.

Consider seeing a doctor if symptoms disrupt your normal routine or you experience insomnia from incessant itching. However, severe cases - when the rash spreads to your eyes, mouth, and genitals, you get an infection, or you develop a fever - require medical attention to avoid complications.

How to prevent a poison ivy rash

You can prevent a poison ivy rash by doing the following:

• Avoid poison ivy altogether: People commonly get a poison ivy rash from outdoor recreation and gardening, and the best way to avoid it is to avoid poison ivy, says Jelesko. Stay on cleared pathways and trails at all times to steer clear of poison ivy, which appears as a cluster of three almond-shaped leaves.
• Wear protective clothing: Protect your skin by wearing long sleeves, pants, socks, and heavy gloves. If you were exposed to poison ivy, machine-wash all your clothes immediately.
• Bathe your pets. Some people develop a rash when they touch their pets that tramped through poison ivy and got urushiol on their fur, says Jelesko. Give your pet a bath to wash off the urushiol, and make sure to wear rubber gloves.
• Wash everything else: Clean everything that got in contact with poison ivy, such as shoes, jewelry, outdoor gear, garden tools, and bags. Urushiol can remain potent for months and years and still cause a rash.

Insider's takeaway

If your skin comes in contact with urushiol - whether directly from poison ivy or from other objects that may have brushed against it - you may develop an itchy, swollen rash with blisters.

You must immediately wash your skin and everything else that was contaminated to rinse out the urushiol. The rash will eventually go away on its own, but you need to see a doctor if you develop a fever or the rash spreads to your eyes, mouth, and genitals.

"The good news is that poison ivy rash symptoms will eventually resolve into normal skin with time, no permanent scarring or disfigurement," Jelesko says.

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