by Deborah Koziara RN, CS-FNP
The following
are some tips on the recognition, signs and symptoms, treatment and prevention
of allergic contact dermatitis caused by poison ivy, oak and sumac.
Definition:
Rhus plants (poison
ivy, poison oak and poison sumac) are the most common cause of allergic contact
dermatitis in the United States. The rash from poison ivy, oak or sumac is
caused by contact with oils found in their sap. The oil, urushiol, is found in
their roots, stems, leaves and fruit and is poisonous at all times of the year,
even when the plant is dead. The sensitivity to urushiol can develop at any
time and the more often you have contact with it, the more likely you are to
develop an allergic rash. Exposure can occur in three ways: 1.) direct
contact-touching the sap of the plant 2.) indirect contact-touching something
that has the oil on it (eg. animal fur, garden tools, clothing, shoes, or sports
equipment and 3.) airborne-oil particles in the air (eg. from burning the
plants, lawnmower or trimmer).
Recognition:
Poison ivy leaves
consist of three pointed leaflets, with the middle leaflet having a much longer
stalk than the two on the side. The leaflet edges can be smooth or toothed.
The leaves range in size from less than ½ inch to 2 1/4 inches in length. They
are reddish when they emerge in the spring, turn green during the summer and
become various shades of yellow, orange or red in the fall. The plant has
small greenish flowers which grow in bunches attached to the main stem and later
in the season has white, wax-like berries which form.
Poison ivy grows as a
vine or woody shrub with hairy roots and it may grow to 10 feet or more,
climbing up trees, walls or fences or as trails along the ground. It is found
in every region of the United States except the Southwest, Alaska and Hawaii.
Poison oak may grow
as a vine but is usually a shrub. It is found primarily on the west coast. It
has three leaves that are shaped somewhat like oak leaves. The underside of the
leaves are a much lighter green than the surface and are covered with hair. It
may develop clusters of green or creamy white berries.
Poison sumac grows as a shrub, especially in swampy locations. Each stem
contains 7-13 leaves arranged in pairs with a single leaflet at the end. It
grows 5-6 feet high with elongated leaves without teeth.
Signs and Symptoms:
The itchy rash of
poison ivy typically appears within 1-3 days after exposure to the urushiol, but
may appear as long as 2-3 weeks after exposure.
Redness and extreme itching,
often accompanied by swelling, are the first signs followed by a pimply red,
rash which later blisters.
The blisters break within
several days, followed by crusting and then disappear.
The worst stage of the rash is
on days 4-7 after exposure to the urushiol oil. The rash may last for 1-2 weeks
and reactions vary from very mild in some individuals to very severe in
extremely sensitive individuals.
Treatment:
If you are exposed
to poison ivy, oak or sumac the first and most important step in preventing the
rash is to wash with soap and water within 5-10 minutes of exposure. After 10
minutes the oils will have penetrated the skin and can’t be washed off. If all
the oils can be washed off within 5-10 minutes there should be no reaction.
Scrub under the
fingernails with a brush, if available, to remove all the oil and prevent
spreading to other parts of the body.
Wash all clothing and
shoes of the exposed person as soon as possible with soap and water.
Also, wash any
sporting, gardening, hunting, fishing or camping equipment that may have touched
the oil.
Urushiol can remain
active on any surface from 1-5 years.
Bathe all animals
that may have been exposed as they can carry the oil on their fur.
Cool compresses of
water or dilute aluminum acetate (Burrow’s solution) may relieve inflammation.
Cool showers or warm baths with oatmeal or baking soda solution may also relieve
itching and promote drying of blisters.
Apply over the
counter lotions and creams, such as calamine lotion or 1% hydrocortisone cream
to decrease itching.
Do not scratch
blisters as it may lead to secondary infection.
Call the doctor if
the rash is severe.
Avoidance:
Learn to recognize and
avoid these plants.
Remove the plants if
growing near your home. Never burn the plants!
Wear long sleeves, long
pants, and socks in heavily wooded areas.
Bathe the family pet if
there is a chance that he/she has had contact with the plants.
Avoid handling objects
which may have touched the plants and if you do touch them wash with soap and
water right away.
Try over the counter
products such as Ivy Block that contains bentoquatam and can protect for up to 4
hours.
Poison Ivy Links
Poison Ivy, Oak and Sumac Information Center
Many pictures used on this page are from
www.poison-ivy.org