The Medical Dermatology Program at Massachusetts General Hospital is a full-service dermatology practice that provides care for all skin, hair and nail conditions.
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The Pediatric Allergy Group at MassGeneral Hospital for Children provides a comprehensive program for diagnosing and treating allergies and asthma.
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What is poison ivy?
There are three native American plants that collectively may be called poison ivy:
These plants can cause an allergic reaction in nearly 85% of the population. To be allergic to poison ivy, you must first be sensitized to the oils. This means that the first time you touch the plant, there may be no reaction. However, the next time there is contact with the plant, a rash may develop.
What causes an allergic reaction?
The resin in the plants contains an oily substance called urushiol. Urushiol is easily transferred from the plants to other objects, including toys, garments, tools, and animals. This chemical can remain active for a year or longer. It is important to know that the oils can also be transferred from clothing and pets, and can be present in the smoke from a burning plant.
What are the symptoms of poison ivy?
The following are the most common symptoms of poison ivy. However, each individual may experience symptoms differently. Symptoms may include:
A contact dermatitis rash characterized by bumps and blisters that itch
Swelling in the area of contact sometimes happens
Blisters that eventually break open, ooze, and then crust over
The symptoms of poison ivy may resemble other skin conditions. Always talk with your healthcare provider for a diagnosis.
Treatment for poison ivy
Specific treatment for poison ivy will be discussed with you by your healthcare provider based on:
Your age, overall health, and medical history
Extent of the condition
Your tolerance for specific medicines, procedures, or therapies
Expectations for the course of the condition
Your opinion or preference
Making sure you avoid the poisonous plants is the best treatment. It is important to teach your family members what the plants look like and not to touch them.
If contact with the plants has already happened, you should remove the oils from the skin as soon as possible by cleansing with an ordinary soap. Repeat the cleaning with the soap 3 times. There are also alcohol-based wipes that help remove the oils. Wash all clothes and shoes also, because the oils can remain on these. You may use calamine lotion or oatmeal baths to help with the itching. Over-the-counter hydrocortisone cream or antihistamines may also help if itching is more severe.
If you have inhaled smoke from a burning plant, if the blisters and rash are on the face, near the genitals, or all over the body, your healthcare provider should be notified. You should also call your healthcare provider if the rash covers a large area of your body, you can't sleep, or you have large blisters. Swelling is a sign of a serious reaction and you should contact your healthcare provider right away, especially if the swelling is on your face or makes an eye close. If you have a serious reaction, you need to see a healthcare provider right away. After a medical history and physical examination, your healthcare provider may prescribe a steroid cream or oral steroids to help with the swelling and itching. This depends on the severity of the rash.
Is poison ivy contagious?
Poison ivy cannot be spread from person to person by touching the blisters, or from the fluid inside the blisters. It can be spread, however, if the oils remain on the skin, clothes, or shoes. This is why washing your hands, clothes, and shoes as soon as possible is very important.
Preventing poison ivy
Tips for preventing poison ivy include the following:
Teach all family members to recognize the plants.
Make sure you wear long pants and long sleeves when poison ivy is in the vicinity.
Wash all clothes and shoes immediately after you have been outside.
Make sure you do not touch a pet that might have been in contact with a poisonous plant.
Wash your hands thoroughly.