A poison ivy, oak, or sumac rash looks like raised, red blister patches or streaks. The rash usually doesn't spread unless urushiol is still in contact with the skin. Poison ivy grows like vines or low shrubs in most climates. Each leaf of a poison ivy plant has three smaller leaflets.
Touching any part of the poison ivy plant can cause redness and swelling of the skin, blisters and severe itching, sometimes hours after exposure. Brushing a poison ivy plant can cause a red, itchy rash. Often, the rash takes on a linear shape (as in the upper left corner of the photo) due to the way the plant spreads across the skin. Poison ivy rash is caused by an allergic reaction to an oily resin called urushiol (U-roo-she-ol).
This oily resin is found in the leaves, stems, and roots of poison ivy, poison oak, and poison sumac. Wash your skin immediately if you come into contact with this oil, unless you know you are not sensitive to it. Washing the oil can reduce the chances of having a poison ivy rash. If you develop a rash, it can be very itchy and last for weeks.
You can treat mild cases of poison ivy rash at home with soothing lotions and cool baths. You may need prescription medication for a severe or generalized rash, especially if it occurs on the face or genitals. Poison ivy rash often appears in a straight line because of the way the plant rubs against the skin. However, if a rash occurs after touching an item of clothing or a pet's hair that contains urushiol, the rash may be more widespread.
You can also transfer the oil to other parts of the body with your fingers. The reaction usually develops 12 to 48 hours after exposure and lasts for two to three weeks. The pus that comes out of the blisters does not contain urushiol and does not spread the rash. However, poison ivy rash is possible if you touch plant resin that is still on the person or contaminated clothing.
If you scratch a poison ivy rash, bacteria under your nails can cause the skin to become infected. See your doctor if pus starts to come out of the blisters. Inhaling urushiol can cause severe shortness of breath and inflammation of the lining of the lungs. A rash from one of these poisonous plants usually manifests as red, itchy bumps on the skin.
The allergic reaction caused by poison ivy is known as contact dermatitis. Occurs when the skin comes into contact with an irritant, such as urushiol. Poison ivy is a common poisonous plant that causes an itchy skin rash. Other poisonous plants that induce eruptions include poison oak and poison sumac.
These plants produce an oily sap called urushiol that causes an irritating and itchy allergic reaction. When you touch a poisonous plant or an object that has been in contact with a plant, you have an itchy rash. This rash is a form of allergic contact dermatitis. The allergic reaction to poison ivy, poison oak, or poison sumac is usually contact dermatitis.
This can occur 24 to 72 hours after exposure. Dermatitis is characterized by itchy bumps and blisters. Sometimes swelling occurs in the contact area. Eventually, the blisters rupture, ooze, and then crust.
The leaves of the poison ivy plant are green in summer, but may turn red, orange, or yellow in spring and fall. Poison ivy is native to all states except California, Alaska and Hawaii, and can also be found in Central America, Mexico and Canada. Calming burn treatment can also relieve itching and inflammation on skin affected by a poison ivy rash. If you touch poison ivy with a pair of pants or a shirt and don't wash it after contact, you could develop another rash if you touch clothes.
Finding poison ivy is easy in the United States, where it grows virtually everywhere except Alaska, Hawaii, and some desert areas of the Southwest. More than 4 in 5 people will develop an itchy, red, inflamed skin rash when they come in contact with poison ivy and its urushiol oil. The sap of the poison ivy plant, also known as Toxicodendron radicans, contains an oil called urushiol. However, touching the vine can still cause a rash because all parts of the poison ivy plant, from roots to leaves, contain urushiol oil, to which between 50% and 70% of American adults are sensitive.
Talk to your doctor if you have a severe poison ivy rash or if the rash affects your face or genital area. The rash occurs only where the vegetable oil has been in contact with the skin, so a person with poison ivy cannot spread it through the body by scratching. Poison ivy grows throughout North America, especially in wooded areas, and touching it can cause an itchy rash in most people. You can also spread the oil to another person if it comes into contact with clothing that has been in contact with poison ivy.