Poison Ivy

Perhaps the least welcome sign of spring in New England is the re-appearance of Poison Ivy, Sumac, & Oak. Be aware that it is possible to be exposed to the oil of these plants during all seasons, including the winter, albeit rare. All three are present throughout most of the country and work exactly the same way: a very sticky but unseen oil from the plant (“Urushiol”) gets onto the skin, triggering a severe allergic reaction known by doctors as “Rhus Dermatitis”.


Within 12-24 hours in sensitive people, longer in less sensitive people, the body produces a local (only where the oil has touched the skin) reaction including intense itching, redness and blistering. This can appear at different times on different parts of the body. The rash does not ‘spread’ but often evolves over several days as the areas of skin initially exposed may react at different times.  Often there is a continued exposure to the oils that have soiled clothing, hats, jackets, shoes or bedding.  Poison ivy usually can be treated at home, and does not need be seen in the office.  However, if your child has fever, severe pain, or severe swelling, especially of the eyes, face, feet, or genetalia, please call the office for a same day appointment.


Unfortunately there is no “cure” for Poison Ivy. It will run its course and go away by itself, but that can take anywhere from a few days to several weeks. Meanwhile, here are some ways to treat the symptoms we find most helpful:

Zanfel – We find this product to be the best treatment, by far, although it is rather expensive. Zanfel is available without a prescription. Some pharmacies keep it behind the counter, however, so you may have to ask for it if you don’t see it on the shelf. Zanfel is a lotion / wash, which when applied directly to the red and blistering areas, controls the itching very well and very quickly. This product should not stay on the skin like a lotion; it must be rinsed off after application. It also serves to wash away the oil from the plant which can be difficult to remove effectively from the skin. 

Benadryl (Diphenhydramine): – this is given by mouth and comes in capsules or liquid form. It does nothing for the rash but it reduces itching. It can also cause sleepiness as a side effect, which could be good or bad. (see Benadryl dosing guidelines).

Caladryl or Calamine lotions: Both are designed to cover the rash and reduce both the redness and the itching. Caladryl is simply Calamine with Benadryl mixed in.  Do not use oral Benadryl and Caladryl together, as this could lead to an overdose as Diphenhydramine can be absorbed into the bloodstream through the skin.

Oatmeal (Aveeno & others) baths or soaks: These are soothing to the irritated skin and also helps with itch control.

Myths vs. Facts:

Eating poison ivy will protect you. This is false, and dangerous!

Scratching will spread the blisters-This is only true if the Urushiol remains unwashed.   If the child scratches before washing and then touches another person or area of their body, the oil can be spread. Once washed by soap and water, Urushiol binds to whatever it is on (skin or clothing) and can no longer be spread. It would be nice if this happened within minutes of exposure, but that’s nearly impossible. Most times parents are unaware of the exposure until the child’s body starts to produce a local reaction.

You must have contact with the plant itself. Actually, the oil can stay active for up to 5 years on any surface including rocks, dirt, toys, dead ivy plants, and the fur of animals (including pets). It can also be spread through smoke in the air when burned. This is why we can, and do, see severe cases of poison ivy at all times of the year.

Some individuals are “immune” to poison ivy. True! This is most common in very young children, who have not been exposed to the urushiol oil in the past, but a lucky 10-15% of older individuals have immune systems that are unable to recognize or react to the oil even after multiple exposures.

Steroids are necessary, or are the treatment of choice. False! While steroids (e.g. Prednisone) are prescribed routinely by many doctors for Poison Ivy, there is actually no scientific proof they work. Steroids are powerful anti-inflammatory drugs more commonly used for serious illnesses like asthma, kidney disease, and lupus.  While they probably do help, they also carry with them very significant risks and side effects. Steroids are “big guns” which are over-prescribed for this problem. They really should be reserved for only the most severe cases.

Prevention is best. The only way to prevent Rhus Dermatitis is to prevent children from coming into contact with the oil, which is found on the leaves. Parents & children should both learn to recognize these plants and stay away from them.  Parents burning leaves in the fall should avoid inadvertently burning Poison Ivy as well. Children should not be allowed to play in areas where poison ivy is known to exist.