Poisonous plants are everywhere in the United States besides Alaska and Hawaii.  Poison ivy, oak, and sumac plants all produce an oily sap called urushiol.  This oil from these plants is what causes your allergic reaction to them.  When coming in contact with poison ivy 90% of people will develop an allergic reaction.  Urushiol oil causes irritation, itching, and a rash.  It can take up to 24-72 hours for a reaction to occur after coming in contact.  An amount of oil that is tinier than a grain of salt is all you need to come in contact with to have a reaction. 

Anyone can have a reaction from one of these poisonous plants but you are at a higher risk if you are camping, hiking, farming, gardening, if you are a landscaper, forestry worker, or a forest firefighter.  



Symptoms occur when you come in contact with the urushiol oil.  You cannot get the rash from someone who is infected as long as there is no oil still present.  The only way to transfer the rash to someone else is from them coming in contact with the oil.  Oils can transfer from anything, skin to skin, clothing, or even your pet. 

Pets do not develop a rash from a poisonous plant, but the oil can stay on their fur. 

Depending on your sensitivity the rash can appear within minutes or hours of coming in contact.  It can take up to 24-72 hours of contact for your rash to appear. 

All the plants cause the same rash and symptoms because it is all caused by the same urushiol oil.  The rash can either be patches or streaks of raised blisters.  The rash may be patchy in just isolated areas or it can cover the entire body depending on sensitivity. 

There are a few stages of symptoms.  The stages start with itching where contact occurred and where the rash will later appear.  Shortly after the itching starts, a rash will appear.  Your rash may develop into fluid filled blisters that will burst and leak fluid.  After the blisters they will crust over and itch again. 

Symptoms can last anywhere from one to two weeks.  Usually all symptoms and discomfort will be gone in 3 weeks. 

It may seem like your rash is spreading.  This rash does not spread.  The rash that looks like it is spreading is just new areas of skin coming in contact with the oil.  The urushiol oil can stay on your towels, clothes, bedding, backpacks, garden tools, or shoes.   



An allergic reaction to a poisonous plant usually doesn’t need medical attention.  If you have severe reactions along with the rash such as nausea, vomiting, shortness of breath, difficulty breathing, hives, fever, swollen lymph nodes, or extreme soreness you will want to seek medical attention. 

There is no way to prevent a poison ivy, sumac, or oak rash once you have come in contact with the urushiol oil.  Once you come in contact, wash the area that is contaminated immediately.  Use lukewarm water with some mild soap to wash away the oil from your skin.  Wash clothing that you were wearing.  Wash everything else.  Anything else you might have transferred the oil onto needs washed.  This could be gardening tools, camping gear, golf clubs, backpacks, or shoes. 

Try to avoid scratching.  Scratching can lead to infections, because of the bacteria on your nails.  If your rash develops blisters, leave them alone, don’t pick at them. 

To help prevent contact with poisonous plants wear clothing that protects your skin.  Long sleeves, long pants and gloves can help. 

Calamine lotions can help with itching and drying up the rash.  Oatmeal baths can be relaxing and help ease the itch.  Anti-itch creams, or steroid creams can help take away the itch as well.  Oral antihistamines is another option.  If the itch is too terrible you can try cold compresses on the affected areas too.  



One way to help prevent contact with poisonous plants is to educate yourself in what these plants look like.  When you think of poison ivy a very common saying is leaves of three leave it be.  This is true with poison ivy.  The leaves grow in groups of three.  The leaves are tear shaped.  Poison ivy can grow up like a vine, or like a shrub depending on what area you live in.  The vine of the plant is hairy and ropelike.  There are no thorns on the plant, and it tends to grow low to the ground. 

Poison oak also grows leaves in three.  The leaves though have rounded tips.  The underside of the leaf is fuzzy.  Poison oak can grow in a shrub or vine form.  The plant will have yellow or white berries.  Poison oak is more common in Western United States. 

Poison sumac can grow in a shrub or tree.  A full grown poison sumac tree can grow up to 20 feet tall.  There are 13 leaflets per stem.  The leaves are smooth and pointed.  It is most common in wooded moist areas.  




READ MORE:  Poison Ivy Allergy

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