©2018 WebMD, Inc. All rights reserved. eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.

Symptoms and Signs of Poison Ivy, Oak, and Sumac

Doctor's Notes on Poison Ivy, Oak, and Sumac

Poison ivy, poison oak, and poison sumac are plants that can cause an itchy, blistering rash when people who are sensitive come into contact with these plants. The rash caused by these plants is an allergic skin reaction to urushiol oil from the plant. Exposure to the oil occurs by touching any part of the plants, touching clothing or other objects that have contacted the plants, touching pets or other animals that have contacted the plants, or by exposure to the smoke of burning plants.

Symptoms of poison ivy, poison oak, and poison sumac exposure include an itchy skin rash that appears within 24 to 72 hours. The rash starts as small red bumps and later develops blisters. The rash may crust or ooze and may appear as red, bumpy lines, or straight lines or streaks on the skin. The rash lasts about two to three weeks. Once the rash goes away it will not recur unless a person is exposed to the plant again.

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Poison Ivy, Oak, and Sumac Symptoms

  • Exposure to poison ivy, oak, or sumac causes an itching skin rash that usually appears within 24-72 hours.
  • The rash usually starts as small red bumps and later develops blisters of variable size. The rash may crust or ooze. It may look like red, bumpy lines or streaks on the skin.
  • The rash may be found anywhere on the body that has contacted the oil from the plant. It can have any shape or pattern but is often in straight lines or streaks across the skin.
  • Different skin areas can break out at different times, making it seem as if the rash is spreading.
  • Contrary to popular belief, leakage of blister fluid does not spread the rash. It is spread only by additional exposure to the oil, which often lingers on hands, clothing and shoes (which are often overlooked as carriers), or tools.
  • The rash caused by poison ivy, oak, or sumac generally lasts about two to three weeks.
  • While poison ivy, oak, or sumac rash can be persistent, these rashes are not recurrent. The rash does not lie dormant and then reappear in the same spot. If you have a bout of poison ivy, oak or sumac that seems to recur, it's more likely you encountered the plant again, or oil from the plants may not have been completely removed from all clothing or surfaces. You may also have a bacterial or fungal infection in the same spot that requires treatment.

Poison Ivy, Oak, and Sumac Causes

The rash caused by poison ivy, oak, and sumac is an allergic skin reaction to an oil called urushiol that is inside the plant. This oil is found in all parts of the plant, including the leaves, stems, roots, and berries.

Exposure to the oil occurs through any of the following:

  • Touching any part of the plants
  • Touching clothing or other objects that have contacted the plants
  • Touching pets or other animals that have contacted the plants
  • Exposure to the smoke of burning plants

Poison ivy, oak, and sumac rash itself is not contagious. However, if oil remains on the skin or on clothing that came in contact with the plants, and the oil comes into further contact with skin, a rash may result. The rash may appear to "spread" because it can develop over several days, or it's possible the oil was not entirely removed from all surfaces.

Risk factors for developing poison ivy, oak, or sumac rash include being in areas where the plants grow, engaging in outdoor activities, and coming into contact with them.

Premenstrual Syndrome (PMS) Track and Prevent Symptoms Slideshow

Premenstrual Syndrome (PMS) Track and Prevent Symptoms Slideshow

A week or two before your period starts, you may notice bloating, headaches, mood swings, or other physical and emotional changes. These monthly symptoms are known as premenstrual syndrome, or PMS. About 85% of women experience some degree of PMS. A few have more severe symptoms that disrupt work or personal relationships, known as premenstrual dysphoric disorder (PMDD).

REFERENCE:

Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

CONTINUE SCROLLING FOR RELATED SLIDESHOW