Summer is when sunshine, warm weather and blue skies call people to enjoy the outdoors.

It's also a time when poison ivy, sumac and oak reek havoc on hikers, gardeners and anyone who crosses their paths.

Where it grows

Natalie Simon, environmental education specialist for McConnells Mill and Moraine state parks, said people in Pennsylvania are less likely to come in contact with poison sumac and oak than poison ivy.

Poison sumac prefers swampy areas, and because it is a large bush most people easily avoid it.

Poison oak prefers the southeast and West Coast and is not really common in the Butler County area.

"Pennsylvania is official out of it's range, which doesn't mean that it's not here, but it's much less common than poison ivy," Simon said.

Poison ivy is prominent in Pennsylvania and does well in commonly traveled places.

"It's very common especially right along the trails and the places where people go, because it grows best in disturbed areas," Simon said.

What it looks like

"The old phrase 'leaves of three, let it be' is a little too general," Simon said. "You'd be afraid to ever go outside."

According to "A Falcon Guide: A Field Guide to Poison Ivy, Poison Oak, and Poison Sumac" by Susan Carol Hauser, poison sumac can be identified by "rabbit-ear" shaped leaflets and drooping berries. The plant can be in a shrub or tall tree form and the leaves always will be in odd numbers.

Eastern poison oak is a non-vining shrub, that has smooth green berries at first which then turn harry and whitish.

The leaves can resemble white oak and usually have three leaflets, but they can have more.

Simon said poison ivy can vary greatly in appearance.

"They are mostly shiny and reddish in the spring, but you can't always go by that," she said.

One of the easiest ways to identify poison ivy is if one or more of the leaves on the leaflet of three has a notch on one side.

"They are asymmetrical and it's kind of like the thumb on a mitten," Simon said.

If a vine is going up a tree in leaves of five, it is more than likely Virgina Creeper. Anything else is probably poison ivy.

"Once they get older and are going up a tree they do not look typical," Simon said. "The leaves are so large you can't tell they are in groups of three, so that can really fool people."

How it affects you

The dangerous part of poison ivy, sumac and oak is not the leaves themselves, but the oil, or urushiol, that they are covered in.

Urushiol can cause different degrees of rashing and itching depending on how allergic the person is to the plant and how much they have been exposed.

Dermatologist Dr. Brad Amos of Cranberry Township treats people affected by poison ivy.

"The giveaway that it is most likely poison ivy is you tend to get linear blisters somewhere on your body where you got the oil from the plant on you," he said.

Simon said it is not true that if a person does not have a reaction to poison ivy before a certain age, they are immune to it.

"There are people who are much less sensitive to it, but I got it for the first time in my 40s," Simon said. "So you can definitely get it, even if you haven't gotten it before."

How to treat it

The first thing to do once a person has come into contact with poison ivy, sumac or oak is wash himself and anything else that made contact with plant.

Simon said it is important to wash the items that made contact with the plant to prevent another reaction.

"It can stay on cloths or tools for months," she said.

Generally a person can use over-the-counter lotions, creams and medicines, such as Benadryl and calamine, to ease the irritation.

If the rash and irritations increase, or if the rash is in a sensitive area like the face, a person should contact either a primary care physician or dermatologist.

"If it's a bad case, you'll want to see somebody as soon as possible," Amos said. "Whoever can see you first would be the one to go to."

Doctors can prescribe a topical or oral steroid to help stop the reaction to urushiol.

"If you give them either topical steroids or oral steroids, it usually clears up pretty quickly," Dr. Amos said.

A person who has poison ivy, sumac or oak should try to resist the urge to scratch the affected area. Scratching it can cause scarring and infection, but it does not spread the oil.

"Once you've taken a shower and washed the oil of the plant off you with soap and water, you cannot get it by touching the blisters or scratching," Amos said.

How to prevent it

Simon and Amos both said preventing contact with poison ivy, sumac or oak starts with education.

"Whenever I give a guided hike or anything involving taking a group outdoors, that's one of the first stops I make," Simon said. "I show them what it is, and I show them how to identify it."

If working outdoors in an area that could have poison ivy, sumac or oak, a person should cover his exposed skin with long pants, shirts and gloves.

Hauser recommends hikers and campers fill a pint or quart jar with rubbing alcohol and carry it with them. Inside the jar they should place half a wash cloth. After exposure the person should slosh the rubbing alcohol onto their skin, but not to the face.

The person should continue to do so periodically for several hours.

Rubbing alcohol is one of the best ways to stop a reaction before it occurs because it neutralizes the urushiol.

Another way urushiol can spread is by pet hair. If an animal gets the oil on its fur, the oil can transfer to people who pet the animal.

If a pet comes into contact with poison ivy, the pet should be washed to prevent the oil from spreading.

How to kill it

Removing poison ivy, sumac and oak can be almost as tricky as avoiding it.

One of the best ways is by spraying it with a weed killer.

"You'll want to spray them because you want to kill the whole thing and the roots," Amos said.

Pulling the plant puts a person in danger of being exposed, and the roots of the plant will continue to grow because they are not killed or cut off from the sun.

Poison ivy, sumac and oak should never be burned. The urushiol can travel into the smoke and into a person's lungs, causing swelling and in some cases death.

"It's very dangerous to sensitive people because it can actually make those blisters occur in the lungs," he said.

Summer is when sunshine, warm weather and blue skies call people to enjoy the outdoors.It's also a time when poison ivy, sumac and oak reek havoc on hikers, gardeners and anyone who crosses their paths.Where it growsNatalie Simon, environmental education specialist for McConnells Mill and Moraine state parks, said people in Pennsylvania are less likely to come in contact with poison sumac and oak than poison ivy.Poison sumac prefers swampy areas, and because it is a large bush most people easily avoid it.Poison oak prefers the southeast and West Coast and is not really common in the Butler County area."Pennsylvania is official out of it's range, which doesn't mean that it's not here, but it's much less common than poison ivy," Simon said.Poison ivy is prominent in Pennsylvania and does well in commonly traveled places."It's very common especially right along the trails and the places where people go, because it grows best in disturbed areas," Simon said.

"The old phrase 'leaves of three, let it be' is a little too general," Simon said. "You'd be afraid to ever go outside."According to "A Falcon Guide: A Field Guide to Poison Ivy, Poison Oak, and Poison Sumac" by Susan Carol Hauser, poison sumac can be identified by "rabbit-ear" shaped leaflets and drooping berries. The plant can be in a shrub or tall tree form and the leaves always will be in odd numbers.Eastern poison oak is a non-vining shrub, that has smooth green berries at first which then turn harry and whitish.The leaves can resemble white oak and usually have three leaflets, but they can have more.Simon said poison ivy can vary greatly in appearance."They are mostly shiny and reddish in the spring, but you can't always go by that," she said.One of the easiest ways to identify poison ivy is if one or more of the leaves on the leaflet of three has a notch on one side."They are asymmetrical and it's kind of like the thumb on a mitten," Simon said.If a vine is going up a tree in leaves of five, it is more than likely Virgina Creeper. Anything else is probably poison ivy."Once they get older and are going up a tree they do not look typical," Simon said. "The leaves are so large you can't tell they are in groups of three, so that can really fool people."

The dangerous part of poison ivy, sumac and oak is not the leaves themselves, but the oil, or urushiol, that they are covered in.Urushiol can cause different degrees of rashing and itching depending on how allergic the person is to the plant and how much they have been exposed.Dermatologist Dr. Brad Amos of Cranberry Township treats people affected by poison ivy."The giveaway that it is most likely poison ivy is you tend to get linear blisters somewhere on your body where you got the oil from the plant on you," he said.Simon said it is not true that if a person does not have a reaction to poison ivy before a certain age, they are immune to it."There are people who are much less sensitive to it, but I got it for the first time in my 40s," Simon said. "So you can definitely get it, even if you haven't gotten it before."

The first thing to do once a person has come into contact with poison ivy, sumac or oak is wash himself and anything else that made contact with plant.Simon said it is important to wash the items that made contact with the plant to prevent another reaction."It can stay on cloths or tools for months," she said.Generally a person can use over-the-counter lotions, creams and medicines, such as Benadryl and calamine, to ease the irritation.If the rash and irritations increase, or if the rash is in a sensitive area like the face, a person should contact either a primary care physician or dermatologist."If it's a bad case, you'll want to see somebody as soon as possible," Amos said. "Whoever can see you first would be the one to go to."Doctors can prescribe a topical or oral steroid to help stop the reaction to urushiol."If you give them either topical steroids or oral steroids, it usually clears up pretty quickly," Dr. Amos said.A person who has poison ivy, sumac or oak should try to resist the urge to scratch the affected area. Scratching it can cause scarring and infection, but it does not spread the oil."Once you've taken a shower and washed the oil of the plant off you with soap and water, you cannot get it by touching the blisters or scratching," Amos said.How to prevent itSimon and Amos both said preventing contact with poison ivy, sumac or oak starts with education."Whenever I give a guided hike or anything involving taking a group outdoors, that's one of the first stops I make," Simon said. "I show them what it is, and I show them how to identify it."If working outdoors in an area that could have poison ivy, sumac or oak, a person should cover his exposed skin with long pants, shirts and gloves.Hauser recommends hikers and campers fill a pint or quart jar with rubbing alcohol and carry it with them. Inside the jar they should place half a wash cloth. After exposure the person should slosh the rubbing alcohol onto their skin, but not to the face.The person should continue to do so periodically for several hours.Rubbing alcohol is one of the best ways to stop a reaction before it occurs because it neutralizes the urushiol.Another way urushiol can spread is by pet hair. If an animal gets the oil on its fur, the oil can transfer to people who pet the animal.If a pet comes into contact with poison ivy, the pet should be washed to prevent the oil from spreading.

Removing poison ivy, sumac and oak can be almost as tricky as avoiding it.One of the best ways is by spraying it with a weed killer."You'll want to spray them because you want to kill the whole thing and the roots," Amos said.Pulling the plant puts a person in danger of being exposed, and the roots of the plant will continue to grow because they are not killed or cut off from the sun.Poison ivy, sumac and oak should never be burned. The urushiol can travel into the smoke and into a person's lungs, causing swelling and in some cases death."It's very dangerous to sensitive people because it can actually make those blisters occur in the lungs," he said.