Rash relief: Treatment for poison ivy, oak and sumac

Source: Best Health Magazine, Summer 2012

You can get it when you go camping or hiking, or even after petting your dog. Poison ivy (or its relatives poison oak and poison sumac) is the world’s most common allergen that causes allergic contact dermatitis; about 50 percent of people are reactive. This rash is the one summer souvenir that no one wants to bring home.

‘The reaction is triggered by urushiol, a sticky oil in the sap of these plants that is easily transferred to skin, clothing and pets,’ says Dr. Shannon Humphrey, a clinical instructor in the department of dermatology and skin science at the University of British Columbia. Exposure typically comes about by touching any part of the plants (even dead ones); by contacting urushiol on other surfaces, such as tools or animals (the latter don’t develop a reaction thanks to their fur); by transferring it yourself through touching one contaminated area of your body before touching another; or by inhaling smoke from burning these plants. Although it’s not contagious, you can also get the condition through contact with urushiol on another person’s skin or clothes.

The first time you’re exposed, you may not have any reaction, or it may take up to three weeks to appear. But on subsequent occasions, ‘it takes just 24 to 48 hours to develop itching, irritation, swelling, redness and blisters’small ones in mild or moderate cases and very large ones in severe cases,’ says Dr. Peter Vignjevic, assistant clinical professor in the division of dermatology at McMaster University. ‘These symptoms can last from one to three weeks and can be serious enough that you’ll miss work, especially if your face or lungs are affected.’ Because the immune system becomes less active with age, kids and young adults are more likely to develop poison ivy than older adults.

Avoiding contact with these pesky plants is the best way to prevent a reaction. Find out whether poison ivy, oak or sumac grows in your area and if so, learn where they’re found and what they look like. When in doubt? ‘The classic memory tip is ‘leaves of three, let them be,”’ says Humphrey. If you think you may encounter them’whether on a camping trip, at a golf course or strolling in an unfamiliar area’protect your skin by wearing long pants, socks, shoes and gloves, and wash your clothes promptly afterwards. Concerned that you’ve already been exposed? Immediately clean with soap and water your skin, nails, clothes, shoes and any tools or gear you had with you. If you do so quickly’within 30 to 60 minutes’then you may avert a reaction or at least reduce its severity, says Vignjevic.

Left untreated, the rash will go away on its own within two to three weeks, although you may develop a bacterial infection if you scratch the affected area with dirty fingernails. If it’s the first time you’ve experienced symptoms, it’s a good idea to confirm your diagnosis with a doctor to rule out other conditions. Seek medical help right away if the reaction is severe; on a large surface area of your body or in sensitive areas such as eyes, mouth or genitals; if the blisters are oozing pus; if you develop a fever; or if you suspect you have inhaled particles. Also check with your doctor if the rash doesn’t begin to clear after one week. Otherwise, seek relief from one of the following over-the-counter remedies.

Topical remedies to soothe itch

Examples: Rexall Hydrocortisone Cream USP 0.5% With Aloe; Bena-dryl Itch Cream; Claritin Skin; Gold Bond Medicated Anti-Itch Cream; Life Brand Hydrocortisone Cream 0.5%; Polysporin Itch Relief Lotion

How they work: Found in the Rexall, Claritin Skin and Life Brand creams, topical hydrocortisone is a steroid that brings down inflammation, redness and itching. ‘It promotes the healing process by decreasing the histamine release and constricting the blood vessels,’ says Ashley Stepaniuk, a pharmacist at Shoppers Drug Mart in Fredericton. Topical antihistamine preparations such as Benadryl, which contains diphenhydramine hydrochloride, counter only histamine (the chemical produced by the body during an allergic reaction), so they can decrease itching but won’t have an effect on swelling and redness. Topical anesthetics like the pramoxine hydrochlor-ide in Gold Bond and Polysporin temporarily numb irritation and itching. Some products also contain menthol (Gold Bond) or camphor (Poly-sporin), which act as safe counter-irritants to distract from the itch, says Humphrey.

Need to know: Treat small affected areas between one to four times daily for up to seven days, avoiding broken skin and the eyes, nose and genitals. Always follow package directions. Because covering with an occlusive dressing, such as an adhesive bandage, will increase the ingredients’ potency too much, apply a thin layer and leave it open to the air.

Oral antihistamines

Examples: Benadryl Allergy Caplets; Claritin Allergy; Reactine Regular Strength

How they work: ‘Oral anthistamines work in the brain to decrease the perception of irritation or itch,’ says Stepaniuk. ‘For poison ivy, Benadryl in its oral form [which contains diphenhydramine hydrochloride] is your first line of defence because it’s best for skin itch. If you can’t take it, then use Reactine [which contains cetirizine] or Claritin [which contains loratadine].’ Says Vignjevic: ‘These treatments won’t help the rash, but will make it less itchy.’

Need to know: While you can take Benadryl every four to six hours, Claritin and Reactine should be taken only once every 24 hours. Benadryl’s major side effect is drowsiness, so avoid taking it if you need to be alert, are driving a car, operating machinery or drinking alcohol. Speak to your doctor before using these if you are pregnant or breastfeeding; have liver disease or glaucoma; have difficulty urinating due to enlarged prostate glands; or are taking sedating medications. Always follow package directions. If symptoms don’t improve after seven days, see your doctor before continuing treatment.

Natural remedies

Examples: Buro-Sol Antiseptic Powder; Aveeno Soothing Bath Treatment; Blairex Wound Wash Saline; Calamine Lotion; Johnson & Johnson First Aid Gauze Pads

How they work: The best natural remedy for acute (new) poison ivy, according to Humphrey and Stepaniuk, is to soak a gauze bandage in a mixture of antiseptic powder (like Buro-Sol) and water, or a sterile salt-water preparation (such as Blairex), and apply it on affected areas several times daily. ‘It not only helps dry out the rash, but also cools the skin and decreases blood flow to the area to help bring down inflammation,’ says Stepaniuk. Although calamine (a mixture of zinc and ferric oxide) acts only on the skin’s surface, it can temporarily cool affected areas and decrease inflammation and itching. Soaking in a bath with Aveeno’s colloidal oatmeal treatment can also soothe itching, although the effect will last only for the duration of the bath.

Need to know: Calamine is safe to use up to three to four times a day, while oatmeal baths can be taken up to twice daily. Apply fresh compresses for up to 20 minutes at a time, four to six times per day.

This article was originally titled "Rash decisions" in the Summer 2012 issue of Best Health. Subscribe today to get the full Best Health experience’and never miss an issue!