Poison Ivy: A common summertime itch
During the summer months, I often encounter many people stopping by the pharmacy with a simple question – What is the best thing to treat poison ivy?
Anyone who spends time outdoors, doing such activities as hiking, yard work, or gardening, runs the risk of encountering poison ivy.
What is poison ivy? Where does it come from? Poison ivy is a type of plant often found in the eastern and southern US. It has leaves that branch out in “threes” from a central stem. The leaves of the plant produce an oil — the fancy name for it is urushiol – that produces a rash with very intense itching when it comes in contact with a person’s skin. Usually the rash shows up a few hours after exposure, although it may take up to 2 weeks after exposure for symptoms to appear.
Poison ivy is related to two other similar plants: poison oak and poison sumac. Because all three plants contain urushiol, the outcome is similar with any of these plants.
The main symptom is very intense itching. Rashes or red lines are also often present. Sometimes blisters may appear, and they can ooze and possibly crust over.
My first recommendation is not to scratch the rash. I realize this is much easier said than done, but scratching the rash can spread the poison ivy chemical to other parts of the skin. Scratching the rash can also lead to the poison ivy chemical getting onto your clothes and causing further spread.
I also suggest washing the affected area with warm, soapy water. If possible, do this while taking a shower. A bath is not as helpful—the oils may disperse, whereas in the shower they are washed down the drain. Exception: If you use colloidal oatmeal in the bath, this may be helpful.
Whatever clothes you were wearing, take them off and launder them. Make sure they are not laundered with other clothes. Also wash any articles that may have come in contact with you or with the plant.
A cool compress may help. If you have a cold pack in the freezer, take it out and, if it’s microwavable, microwave until it is cool (maybe 20 seconds). Then apply to the affected area for five minutes.
Several non-prescription medications are available. Calamine lotion, which contains zinc oxide, seems to be one of the most effective, compared with other non-Rx products. This product—sometimes called an astringent–dissolves oils on the skin, including urushiol. Once dissolved, the oil is less likely to cause symptoms. It is applied every 6 to 8 hours as needed for itching and other symptoms.
Another non-Rx item that may help is hydrocortisone 1% cream. Hydrocortisone can suppress inflammation in the skin. Suppression of inflammation may decrease the discomfort. It is recommended that you apply it four times a day as needed.
Colloidal oatmeal is another non-prescription item that may help. Like hydrocortisone, it can suppress inflammation on the skin, albeit a little bit differently, and as a result possibly provide some relief.
What about antihistamines? They are for itching and rashes, right? Well, yes, but research shows that they do not help all that much with poison ivy. Why? Histamines, which the human body produces in an allergic reaction, do NOT play a significant role in the body’s reaction to poison ivy. Thus antihistamines—which only work on the body’s histamine response—are of little use. One could perhaps use diphenhydramine if the itching is at night and is leading to insomnia, or difficulty sleeping. Diphenhydramine is so likely to make you sleepy that the US Food and Drug Administration began recognizing it as an antihistamine AND a sleep aid. However, it is still not the top choice for poison ivy itself.
There are also several cleansers that have camphor and menthol that are available. Not as much is known about how effective these are. They can provide relief by delivering what feels like a “cooling” effect, but the urushiol may still remain, so the itching may continue when the product wears off. Warm soapy water in the shower may be just as effective or even more so.
If you do try hydrocortisone, colloidal oatmeal, and/or calamine, and are still having symptoms after seven days, see your physician. The main reason for this: Some cases of poison ivy may only respond to prescription products. Most of these products are steroids similar to non-rx 1% hydrocortisone, but are more effective and often work when the hydrocortisone is insufficient.
See your physician immediately (i.e. do not wait 7 days) if the patient is two years old or less, if the swelling and/or itching is severe, if it covers large areas of the body, or if it is on the eyes, ears, nose, mouth, or genital areas.
I hope you have an enjoyable summer, free of the itch associated with poison ivy.
– The Helpful Pharmacist