Preventive tips to avoid plant-caused skin reactions
Posted Feb 16 2011 12:00am
AAD.org - What may start as a seemingly harmless day of gardening or yard work can quickly take a turn for the worse when common plants make their mark on the skin, causing a host of mild to even severe skin reactions. That is why dermatologists are arming outdoor enthusiasts with preventive tips to keep these perils of the great outdoors at arm’s length.
Speaking at the 69th Annual Meeting of the American Academy of Dermatology (Academy), dermatologist Julian J. Trevino, MD, FAAD, associate professor of dermatology at Wright State University Boonshoft School of Medicine in Dayton, Ohio, discussed common skin reactions that can occur from contact with plants, including effective treatments and preventive tips and strategies.
“While most of the skin reactions resulting from direct contact with a hazardous plant are more of a nuisance than anything else, there are some instances where the reaction can affect the entire body and pose a potentially more serious risk,” said Dr. Trevino. “For example, people who are allergic to plants or have sensitive skin that is prone to eczema or atopic dermatitis may experience more severe or long-lasting effects that require medical attention.”
There are many outdoor plants that can cause an adverse skin reaction simply by brushing up against them. One group of plants in particular that causes toxin mediated urticaria (hives) is stinging nettle plants, which have sharp hairs that produce irritants. These irritants are chemicals, such as histamine or acetylcholine, which usually cause an immediate outbreak of hives within 30 to 60 minutes upon exposure. Most people would experience a mild reaction with hives that resolve on their own in a few hours.
Dr. Trevino also explained that people who handle food frequently or those with a tendency toward eczema can develop an allergic reaction to plants known as immunologic contact urticaria. This reaction usually results from susceptible individuals coming in contact with various fresh fruits and vegetables, herbs, nuts, shrubs and grasses. In this instance, a person usually experiences itching and hives within 30 minutes. In its more severe form, this reaction can involve not only hives on the skin, but also swelling in the throat, lungs or gastrointestinal tract that requires immediate medical attention.
Another common cause of skin irritation from plants stems from exposure to spines or glochids - tiny emergences of certain cacti or prickly pear plants – which can get caught in the skin and cause an itchy rash. Since these tiny spines break the skin, Dr. Trevino cautioned that a person could develop a staph or fungal infection if bacteria or fungus are present on the prickly spine that enters the skin - leading to a more serious situation.
“The spines from the plants should be carefully removed from the skin, usually with tweezers or a piece of tape that is placed over the area where the spine entered the skin and gently torn away with the tip of the spine attached,” said Dr. Trevino. “Minor itching, irritation or rash can be typically treated with an oral antihistamine or over-the-counter topical steroid, but when a rash doesn’t respond to over-the-counter treatments, you should see a dermatologist. In cases where a rash is accompanied by more severe reactions such as difficulty in breathing or swallowing, a person should go to the emergency room immediately.”
Perhaps the most well-known and feared plants linked to skin rashes and irritation are poison ivy, poison oak and poison sumac. Dr. Trevino explained that these plants contain a resinous sap called urushiol that can cause a rash when it comes in contact with the skin in the estimated 50 percent of the population that is allergic to these plants. However, Dr. Trevino added that direct contact with poison ivy and its variants is not the only way that people can get this bothersome rash.
“When a poison ivy plant is injured in any way, the urushiol is released quickly and can stick to anything around it,” said Dr. Trevino. “That means that you can develop poison ivy if you pet your dog after he has come in contact with the plant, or if you touch a gardening tool or piece of clothing that has come in contact with poison ivy. Even airborne contact with urushiol is possible, especially in the fall or winter when these poisonous plants are burned among other brush and particles of urushiol are released into the air. If these airborne particles land on your skin or you inhale them, you can get a widespread rash and severe irritation in the respiratory tract.”
When a person with poison ivy allergy contacts the plant, Dr. Trevino explained that time is of the essence to prevent a rash. The area that has been exposed should be rinsed off immediately with water. This can remove at least some of the resin before it is absorbed in the skin. To treat a rash caused by poison ivy, lukewarm baths and soaks with products containing aluminum acetate (a type of salt that dries up the weeping and blisters), and topical preparations such as calamine or topical steroids are helpful. While oral antihistamines will help alleviate itching and skin irritation, topical antihistamines should be avoided – as some people are allergic to them and the rash could get worse.
“In some cases when a rash is severe or covers a large area of the body and is not getting better with over-the-counter therapies, a dermatologist may prescribe strong topical steroids or a course of steroids taken orally,” said Dr. Trevino.
To minimize the risk of such skin reactions, Dr. Trevino recommended the following tips:
• Wear protective clothing whenever possible – including gloves (preferably vinyl gloves), long sleeves and long pants tucked into socks.
• Apply an over-the-counter barrier cream or lotion containing quaternium-18 bentonite to exposed skin before going outdoors. This helps prevent urushiol from poisonous plants from contacting the skin.
• Avoid poisonous plants (remember this phrase: “leaves of three, let it be”).