However, it turns out that there are many myths regarding obtaining and treating poison ivy. Two Harvard dermatologists give the facts below to help you avoid — or manage — poison ivy.
How can you be exposed to poison ivy? "When I was a child, my parents informed me that poison ivy could only be contracted by touching red, shiny leaves," says Dr. Abigail Waldman, a dermatologist at the Harvard-affiliated Brigham and Women's Hospital. She emphasises that this is not true. Urushiol, the allergen-causing substance, is present throughout the year in all parts plant components, including the leaves, stems, bark, fruit, and roots.
Brushing up against any of the plant's parts or touching anything that has come into contact with the plant – your clothes, shoes, gardening tools, or your pet — can result in an allergic reaction. I don't recall being near any poison ivy, but it's likely that my dog got the oil on my hands and arms when removing her harness when we arrived home from a walk.
To avoid poison ivy, wash your hands as soon as possible.
If you've been exposed to urushiol, wash the affected area with soap and water (preferably dish soap) as soon as possible, ideally within an hour. "You should also wash anything that has been contaminated - not only your clothes, but also things you don't ordinarily wash, like your jacket and shoes,"
A rash may not appear right away.
You can develop symptoms – a red, itchy rash with blisters — four hours to four days after being exposed to urushiol. Why is there such a significant delay? Poison ivy rash is a type of allergic contact dermatitis. T cells, the immune cells that recognise and attack foreign molecules — in this case, skin proteins that react with urushiol — mediate it.
According to Dr. Jeff Yu, assistant professor of dermatology at Harvard Medical School, "T cells take 24 to 96 hours to ramp up in the body, which is why this is also known as a delayed-type hypersensitivity reaction." After your first poison ivy encounter, symptoms take longer to appear. "However, once your body has been exposed and reacted numerous times," he continues, "it tends to show up faster since your body'remembers' the rashes and has T cells ready to go."
This reaction is distinct from more common allergies, such as those to cats, dogs, or mould, which are hypersensitive reactions that occur immediately. Histamine, a molecule that plays a part in reactions like a runny nose and watery eyes, mediates these within minutes.
I had unknowingly transported urushiol to other portions of my body, including my torso, because I hadn't realised I'd been exposed to it. Fortunately, once the oil is removed, the rash is not communicable – it cannot be spread to other regions of your body or to other people, according to Dr. Waldman.
When treating poison ivy, begin with over-the-counter medications.
Simple therapies may suffice for lesser cases of poison ivy, according to Dr. Yu, who treats patients at the Contact Dermatitis and Occupational Dermatology Clinic at Massachusetts General Hospital. If you have a very mild case that is localised to one spot on an arm or leg, Dr. Yu recommends applying a thin layer of topical 1% hydrocortisone cream to the affected area. He also recommends using topical anti-itch products such as calamine lotion or Sarna lotion with menthol.
Hydrocortisone cream did not help me. "Once poison ivy has spread, applying topical hydrocortisone is like sprinkling water on a wildfire," Dr. Yu says. A friend brought me a rash-relief spray, which was calming but only provided temporary relief. Another person suggested that I try the antihistamine diphenhydramine (Benadryl), an over-the-counter allergy medication. According to Dr. Yu, this is ineffective since histamine does not play a significant role in poison ivy. "The main advantage of Benadryl is that it makes you tired," he says. Although it did make me asleep, I was still itching and uncomfortable.
So, what works if over-the-counter medications are ineffective and your symptoms are interfering with your life? Oral steroids may be prescribed by a doctor. Indeed, I felt significantly better after visiting an urgent care centre and starting the oral steroids advised by my doctor. Make sure to carefully follow the dosing instructions: To avoid a flare-up, oral steroids must be tapered, which involves gradually taking lesser doses over three weeks. Always seek medical attention if a poison ivy rash affects sensitive areas of the body, such as the face or groin.
Refrence: Havard Health
