Allergies to Poison Ivy, Oak, and Sumac
What Are the Symptoms of a Poison Plant Reaction?
The symptoms of a poison plant reaction are similar, because they all contain the same chemical, urushiol. Symptoms generally occur in the following phases:
- Redness and itching of the skin.
- A rash erupts on the skin, often in a pattern of streaks or patches from where the plant has come into contact with the skin.
- The rash develops into red bumps, called papules, or large, oozing blisters.
How Common Are Poison Plant Allergies?
Poison ivy, poison oak, and poison sumac are three of the most common causes of allergic contact dermatitis in North America. Some experts estimate that three out of four people are sensitive to the chemical found in these plants, although the degree of sensitivity varies. Some people are very sensitive and will have a quick reaction upon contact with a small amount of urushiol. For those who are less sensitive, exposure to a large amount of urushiol is necessary before a reaction develops. Cases of poison plant allergy occur most frequently during the spring, summer, and early fall when people spend more time outdoors.
How Are Allergies to Poison Plants Diagnosed?
An allergy to a poison plant is diagnosed based on the typical pattern of symptoms and the appearance of the rash.
How Are Allergic Reactions to Poison Plants Treated?
An allergic reaction to a poison plant cannot be cured, but the symptoms can be treated. You may take cool showers and apply an over-the-counter lotion -- such as calamine lotion -- to help relieve the itch. If your reaction is more severe or involves mucus membranes (membranes found in the eyes, nose, mouth, and genitals), you may need a prescription drug, such as prednisone, to help control the reaction.
How Long Does a Poison Plant Rash Last?
Most rashes caused by poison ivy, poison oak, or poison sumac are mild and last from five to 12 days. In severe cases, the rash can last for 30 days or longer.
Does Immunotherapy Help With Poison Plant Allergies?
Immunotherapy is not available for allergies to poison ivy, poison oak, and poison sumac.