Poison Ivy, also known as rhus dermatitis, is caused from an allergic reaction to the oil resin, urushiol, found in the leaves, stems and roots of poison ivy, poison oak, and poison sumac. It is very common in the summer months.
The classical rash is a red blistering eruption seen in straight lines due to the way the plant brushes against the skin. If contact to the resin is a result of touching a piece of clothing, or from touching a pet that has been romping through the woods, the rash may appear more spread out. Inhaling smoke from a burning poison ivy, sumac, or oak plant may even cause a dangerous irritation to the nasal passges and lungs.
Once the oil resin is on the skin, it can spread to other parts of the body by scratching. Rhus dermatitis is often a very itchy rash and if untreated may last for several weeks. The rash itself is NOT contagious.
If contact to any of these plants occurs, immediately rinse yourself off with lukewarm water. Use a cleanser to wash away any remnant oil resin from your skin. Oil from poison ivy can stick to many different surfaces. Wash the clothing that may have contacted the plant. Rinse off patio furniture, garden tools, golf clubs, and even the fur on a pet.
A mild case of poison ivy may be treated at home with calamine lotion, over-the-counter hydrocortisone cream and oral antihistamines to control the itch. Do not open a blister as this may lead to infection. Cool compresses may help relieve the itch. If the rash is severe or widespread, affects the face or genitals, if blisters are oozing pus, or if a fever develops, seek medical attention immediately.