Poison ivy and ragweed are often confused. The two plants however, are very different. Ragweed, or rather its pollen, is one of the main causes of hay fever, while poison ivy is a plant that triggers an irritation when it comes into contact with the skin. It is typically found at the edge of wooded areas, along creeks and other wastelands. In terms of appearance, its almond-shaped leaves have distinctive jagged edges and grow in groups of three.
Poison ivy contains an oily resin (urushiol) that causes an allergic skin reaction in the vast majority of those who come into contact with it. It is the resin, found everywhere in the plant, that causes the irritation. The resin is still present and is just as harmful when the plant is dead, has been ripped out of the ground, or has wilted or dried. Reactions do not occur immediately. They tend to appear 7 to 10 days after initial contact and more quickly, within 8 hours to 2 days, upon re-exposure.
Poison ivy causes contact dermatitis which, simply put, is an inflammation of the skin. It typically causes redness, swelling and itching. Blistering may also occur and, in more severe cases, the person reacting to the poison ivy may experience significant discomfort that interferes with daily functioning.
Hands are most commonly affected since they usually come into contact with countless objects. No part of the body however, is immune. Blisters can occur at different times in different people. For example, they can develop on the arms several days after appearing on the hands. This does not mean that the reaction is spreading from one area of the body to another. The fluid that leaks from blisters is not contagious.
The inflammation usually disappears within 7 to 21 days.
Dermatitis can develop as a result of direct contact between the skin and the poison ivy resin or through indirect contact. In fact, the resin responsible for the allergic reaction can be transferred from the plant to other objects such as pet fur, clothing and tools. The resin can remain active, and can retain its harmful effects.
If you come into contact with poison ivy, wash hands thoroughly with cold water and a touch of soap, as soon as possible. Although this will not prevent the allergic reaction from occurring, it will stop it from spreading. To prevent further contamination, it is also important to wash any clothing, tools or pets that may have come into contact with the plant.
Once symptoms appear, apply cold compresses or calamine lotion to dry the blisters and relieve itching. Taking a bath in colloidal oatmeal may also help alleviate itching. It is important to avoid scratching as this may lead to infection. A cortisone-based lotion may also help soothe itching and promote healing. The use of oral antihistamines or topical antihistamine or antibiotic creams are not recommended. If the affected area involves the face or genitals, it is strongly advised that you see a doctor.