Ragweed, poison ivy and our health

Ah, the joys of summer with its blooming flower beds, thriving gardens and rich colours and scents that stimulate our senses. But summer also means exposure to certain wild plants, like ragweed and poison ivy, which can spoil some of that seasonal enjoyment. Let’s learn more about them.

Ragweed

Ragweed (Ambrosia artemisiifolia), a very widespread plant, is one of the leading causes of hay fever, also known as seasonal allergic rhinitis (as opposed to perennial allergic rhinitis, which lasts all year). Only people allergic to its pollen will present allergy symptoms, including:

• Runny nose, sinus congestion and bouts of sneezing
• Red, swollen, watery, irritated eyes
• Respiratory problems, coughing and asthma

Ragweed does not trigger an allergic reaction when touched.

With its green, jagged leaves similar to those of the carrot plant, ragweed is easy to recognize. It can reach a height of 1.5 metres.  It starts growing in May, blossoms in July and pollinates from August to October, which is when it causes hay fever symptoms. It then dies in fall, after the first frost.  Ragweed is commonly found in southern Quebec (Outaouais, Montreal and Montérégie), where it grows in urban areas, agricultural fields and along highways.

How to reduce hay fever symptoms

If you have hay fever, there are precautions you can take to limit your exposure to ragweed pollen and minimize its impact:  

• Pull it out before it blooms.
• Try to do your outdoor activities at the end of the day.
• Close the windows of your home and car.
• Do not use the clothesline to dry clothes and sheets.
• Shower before going to bed.
• Take allergy medication (Reactine®, Allegra®, Aerius® or Claritin®).

How to relieve hay fever symptoms

There are many over-the-counter medications that work well to relieve allergy symptoms:

• Oral antihistamines act on the entire body and reduce allergy symptoms as a whole. For best results take them every day for the entire allergy season once your symptoms start. To prolong the use of an antihistamine beyond this period, please consult your doctor.

• Other medications target specific symptoms, such as nasal congestion or eye irritation. They come in many forms, including syrups, tablets and eye drops, and may be used in combination with oral antihistamines. But before taking more than one medication, always read and follow the label or speak with your family pharmacist for advice.

Warning!

• Some products contain both an antihistamine and a decongestant. If you take this type of product, do not use a separate decongestant.
• Nasal spray decongestants may create a rebound effect and dependence if used for more than 3 consecutive days. Saline sprays are an excellent alternative to consider.

Poison ivy

Poison ivy (Toxicodendron radicans) grows along the edges of wooded areas, riverbanks and highways. It is known for the painful, itchy skin rash (contact dermatitis) it causes due to a substance called urushiol found in its sap.

The reaction to poison ivy is a type of allergy, which means you may not develop symptoms the first time you are exposed to it, but rather the second time. Symptoms generally start 24 to 48 hours after direct or indirect (e.g. touching the contaminated fur of an animal) contact and include:

• Intense itching
• Red, painful, inflamed rash
• Blisters

It takes 7 to 15 days for symptoms to disappear. Remember that most people will develop a reaction to poison ivy.

Poison ivy is a perennial plant that can grow as a climbing or trailing vine or a shrub. It produces small white berries in September and its leaves are reddish in the spring, dark green in the summer and multicoloured in the fall. Each of its leaves has three almond-shaped leaflets.

What to do after contact

• Wash the exposed area with cold water and soap, a mixture of water and vinegar (2 Tbsp of vinegar in 1 cup of water) or water and rubbing alcohol (½ cup of alcohol in ½ cup of water).
• Wash your clothing and other contaminated items several times in hot soapy water.
• Wash your pet if it has been in contact with the plant.

If you have a poison ivy rash, talk to your family pharmacist. He or she may suggest one of the following treatments to help relieve the itchiness:

• Use cold compresses.
• Take an oatmeal bath (colloidal oatmeal treatments are available over the counter).
• Apply calamine lotion.
• Use an oral or topical antihistamine.
• Apply a cortisone cream.

If symptoms are severe or widespread, if you develop infection (pain and pus) or fever, be sure to see your doctor. You may need antibiotics.

Pharmacy services

Your family pharmacist is well qualified to give you the right advice when you run into minor health problems.  Just ask!