Ask the Pharmacist

Q: I have relatives coming to our area to visit for the next week or so. They’re not used to rural life. How should I educate them about poison ivy and if they get it, how is it best treated?

A: Along with amazing beaches, beautiful sunsets and more bagpipes than you can shake a stick at, Bruce County is also home to its share of poison ivy. For those who do not know what it looks like, an encounter with this plant or its close relatives (poison oak and sumac) has the ability to put a damper on the entire holiday.

The first order of business is to be able to recognize the plant. Most of us know that poison ivy grows as a shrub or vine and is commonly found in open fields, wooded areas, along a riverbank, along a roadside and, unfortunately, sometimes in parks and backyards as well. Its size ranges from a few centimetres off the ground (when it looks more like a ground cover) to an upright plant that can reach two to three feet in height. Poison ivy can also appear as a vine that can twine around a tree or post.

The key feature of this plant is that regardless of size, the leaves occur in clusters of threes, with the middle one being larger. The leaves join together at a single stalk the other end of which is attached to the “woody” stem of the plant at a node. As you look up the stem, the leaf clusters alternate as to which side of the stem they grow off of. The colour and shape of the leaves may also vary depending upon the exact species, the local environment and time of year.

In the spring or early summer, the leaves appear reddish or bronzy green. As the summer progresses the colour of the leaves will change to somewhere between a deep to bright green. Come the autumn, the leaves will be a wine-red to vivid orange-red colour in sunny areas whereas more shaded areas will result in the leaves turning a dull tan or light-brown.

In the spring, some plants will have greenish-white flowers and in the fall many will have grayish to white waxy looking berries that grow after the leaves have departed. With so much variability, it is a challenging plant to identify even for long-time local residents.

Poison ivy and its cousins are one of the most common causes of allergic contact dermatitis in Canada, affecting millions annually. The chemical urushiol, found in the plant’s leaves, stem and roots, is invisible and spreads easily. Between 80-85 per cent of people who come in contact with it will have an allergic reaction, with 10-15 per cent of those having a reaction that would be deemed severe in nature.

The characteristic rash develops quickly (within hours to two days) and can last weeks or even a month or two in those whose immune system reacts particularly violently to the chemical. The rash is initially red, itchy and may be raised. This mild reaction can progress to a much deeper red colour and be accompanied by bullae (a bubble-like cavity filled with fluid), papules (small red raised swellings that look like a pimple and are not filled with pus), and more severe inflammation and swelling.

Treatment is the same regardless of whether the reaction is to poison ivy, oak or sumac, and is based on numerous studies that have tried to root out the facts from fiction. The first thing to know is what not to waste your money on.

Antihistamine creams (such as Benadryl), anaesthetic rub-ons (which are all the products that contain the “caine”-like ingredients such as Solarcaine) and antibiotic creams (such as Polysporin), do not work and, in fact, seem to increase the risk of you suffering an allergic reaction to them.

The initial treatment step should be to wash the affected areas with plain soap and water thoroughly. A topical (i.e. applied to the skin) skin cleanser can be used but there is no proof it works better and it's more expensive.

An astringent, such as Buro-Sol, witch hazel or one of the other commercially-available products (such as from Neutrogena or one of the many ones found in the acne section of a store), can help relieve the itching and dry the weeping rash. Calamine can also help for this, although the feedback we have received over the years has not been incredibly positive.

An oatmeal-based bath product (also available from Aveeno among other companies) can also be very helpful for both of these symptoms. A topical analgesic (such as one of the Gold Bond products) can be safely added to help manage the itch. An over-the-counter cortisone cream may be more effective than these analgesics although still too weak to help those with more severe reactions.

Unfortunately, antihistamines that come in a pill form (Aerius, Reactine, Benadryl) do not appear to help, since the allergic reaction to urushiol is not mediated by the release of histamine as so many other allergic reactions are.

For those not helped by these measures, the next step is a visit to a physician where a more powerful prescription cortisone-type cream will probably be prescribed (such as betamethasone) and the use of an oral steroid (such as prednisone) will be debated, depending on just how severe the reaction is.

These products tend to work better if they are initiated before vesicles appear, so seeking help early when initial measures fail should be a priority.

For more information about this or any other health-related questions, contact the pharmacists at Gordon Pharmasave, Your Health and Wellness Destination. Also check the website at www.gordon-pharmasave.com/ and the Facebook page at www.facebook.com/GordonPharmasave/?fref=ts