Q: My kids love exploring the woods behind our house, and I'm worried that this summer will bring about the first case of poison ivy. What is the best way to treat a reaction should they experience one?

Q: My kids love exploring the woods behind our house, and I'm worried that this summer will bring about the first case of poison ivy. What is the best way to treat a reaction should they experience one?

A: Some of the most common poisonous plants include poison ivy, poison oak and poison sumac. Upon exposure, the immune system revs up and attacks the plant oil. This results in an allergic reaction, causing an irritating rash.

Pets, clothing and tools can spread the oil. And since the oil remains allergenic for years, unsuspecting spring gardeners can get the rash from last season's gloves and shovels.

If you come into contact with these poisonous plants, you should wash well with plenty of soap and water. Unfortunately, this won't always prevent the rash because the oil bonds fast to human skin and is nearly impossible to remove within 30 minutes of exposure.

Once you have the rash, it typically lasts two to three weeks. Meanwhile, you can treat the symptoms and prevent infection. For mild cases, over-the-counter hydrocortisone cream and oral antihistamines such as Benadryl work well to control inflammation and itching. Topical antibiotic ointment may prevent bacterial infection when the skin is broken open from repeated scratching.

If you have widespread rash, face or genital involvement, or signs of infected skin, it's time to see your doctor. In these cases, prescription steroids or antibiotics might be necessary.

Prevention by avoidance is best, so take the time to learn about and recognize these plants. Be sure to consult your child's primary care physician with questions and concerns.

-Dr. Michael D. Patrick Jr. is a member of the Section of Emergency Medicine, Medical Director of Interactive Media for Nationwide Children's Hospital and an Assistant Professor of Clinical Pediatrics at the Ohio State University College of Medicine.