According to the American Academy of Dermatology, a poison ivy rash can last three weeks or longer if you've never experienced it before. Otherwise, it may take two weeks or less before the rash goes away on its own. Most poison ivy cases go away on their own within 1 to 3 weeks. After about a week, the blisters should begin to dry out and the rash will begin to disappear.
Severe cases can last longer, have worse symptoms, and cover more of the body. Most eruptions caused by poison ivy, poison oak, or poison sumac are mild and last five to 12 days. In severe cases, the rash may last 30 days or longer. A poison ivy rash usually lasts 1 to 3 weeks.
However, you should consider going to the doctor if the rash doesn't improve after a week or if it seems to be infected. In the meantime, you may find some relief by cleaning your skin with soap and water, washing all clothes and objects that may have been in contact with poison ivy, and applying cold compresses to your skin. Resist the urge to scratch and leave blisters alone as they form. Finally, taking antihistamine pills and applying hydrocortisone cream or calamine lotion may offer you some relief.
Urushiol in the sap, which is responsible for allergic reactions, is an oily substance that does not evaporate. Therefore, it can remain poisonous for several months. Be sure to take precautions when handling contaminated items or dry or dead poison ivy plants. It takes a while for the rash to appear.
A rash may occur within a few hours if you have had a rash from any of these plants before. If you've never had a rash from poison ivy, oak, or sumac, it can take 2 to 3 weeks before you see a rash. These medications aim to reduce or eliminate the effects of histamine, but poison ivy does not cause the release of this substance. You may come into contact with poison ivy during outdoor activities, such as during forest walks.
If your skin comes into contact with urushiol, either directly from poison ivy or other objects that may have rubbed against it, you may develop an inflamed, itchy rash with blisters. Poison oak looks a lot like poison ivy, although it generally looks more like a shrub and its leaves are shaped similar to oak leaves. Keep in mind that antihistamines (medicines used to treat allergies) do not directly affect allergic reactions to poison ivy. The first sign of an allergic reaction to poison ivy is a strong itch with redness at the site of contact.
Symptoms may be more severe in people who have had a significant allergic reaction to poison ivy in the past. When the skin comes into contact with poison ivy sap, a painful allergic reaction called “contact dermatitis” or “Rhus dermatitis” can occur. Symptoms of an allergic reaction to poison ivy usually appear 24 to 48 hours after contact with the sap. It's important to note that there are over-the-counter products that are marketed to reduce symptoms of poison ivy rash, but their effectiveness is rarely supported by well-controlled clinical trials, Jelesko says.
Poison ivy, poison oak, and poison sumac produce urushiol, an oily sap that causes an allergic reaction when it comes into contact with the skin.