Summer is the perfect time for hiking, camping, and spending time outdoors, but in forested areas, poisonous plants can quickly become a nuisance when walking through the woods. Poison ivy is a common plant that causes rashes when touched, but how does it work, and are some people immune to it? Read on to learn more:

What Does Poison Ivy Look Like?

The old pneumonic “leaves of three, leave them be” is an excellent way to remember what poison ivy looks like, but there are quite a few three-leaved ground plants that may dot the forest. Poison ivy grows leaves in groups of three to a stem, and its leaves are relatively round and flat. Beatrice Murch’s photo of poison ivy in the woods is an excellent reference to go by.


Poison ivy rashes appear red and bumpy on the skin, and they may blister. These rashes are also very itchy.

How Poison Ivy Gives You a Rash

Poison ivy and its cousins, poison oak and poison sumac, give rashes the same way: they release a chemical called urushiol. This natural oil acts as a defense system for the plant and is released when the plant is injured, bruised, or burned. When urushiol comes in contact with our skin, it can cause an allergic reaction. We don’t need much exposure to develop a rash either-- only 50 micrograms are required to start the reaction. That’s less than a grain of table salt!

Can Someone be Immune to Poison Ivy?

In short, no one is truly immune to poison ivy. Each time someone is exposed to poison ivy, their immune system recognizes the urushiol as a skin irritant. Thus, it prepares the body for future exposure, and a rash will form when it comes in contact with the skin again. The myth of immunity to poison ivy comes from our first exposure to it before the body realizes it’s an irritant. While it takes longer for some immune systems to react, the skin rash is just the body’s reaction to urushiol. Some people may be less sensitive to it than others, but everyone has the potential to react.

Treating Poison Ivy Rashes

Most poison ivy rashes can be treated at home using over-the-counter products:

  • Over-the-counter allergy medications like Benadryl can help reduce itching and swelling around the rash.
  • Cortisol can help reduce itching as well over the first few days.
  • Lotions with menthol can help the area stay moisturized.
  • Taking cool baths or using cool compresses can help bring down swelling and pain as well.

Typically, a poison ivy rash only lasts a few days and will go away on its own with proper attention and care. However, if a rash lasts over a week or is widespread and continues to blister, speak with your doctor immediately.

Paying for Necessary Medical Supplies
Poisonous Plants and How to Handle Them

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