Poison Ivy Exposure
Fast action needed
Because urushiol can penetrate the skin within minutes, there's no time to waste if you know you've
been exposed. "The earlier you cleanse the skin, the greater the chance that you can remove the urushiol
before it gets attached to the skin," says Hon-Sum Ko, M.D., an allergist and immunologist with FDA's
Center for Drug Evaluation and Research. Cleansing may not stop the initial outbreak of the rash if
more than 10 minutes has elapsed, but it can help prevent further spread.
If you've been exposed to poison ivy, oak or sumac, if possible, stay outdoors until you complete
the first two steps:
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First, Epstein says, cleanse exposed skin with generous amounts of isopropyl (rubbing) alcohol.
(Don't return to the woods or yard the same day. Alcohol removes your skin's protection along with
the urushiol and any new contact will cause the urushiol to penetrate twice as fast.)
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Second, wash skin with water. (Water temperature does not matter; if you're outside, it's likely
only cold water will be available.)
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Third, take a regular shower with soap and warm water. Do not use soap before this point because "soap
will tend to pick up some of the urushiol from the surface of the skin and move it around," says
Epstein.
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Clothes, shoes, tools, and anything else that may have been in contact with the urushiol should
be wiped off with alcohol and water. Be sure to wear gloves or otherwise cover your hands while doing
this and then discard the hand covering.
Dealing with the rash
If you don't cleanse quickly enough, or your skin is so sensitive that cleansing didn't help, redness
and swelling will appear in about 12 to 48 hours. Blisters and itching will follow. For those rare
people who react after their very first exposure, the rash appears after seven to 10 days.
Because they don't contain urushiol, the oozing blisters are not contagious nor can the fluid cause
further spread on the affected person's body. Nevertheless, Epstein advises against scratching the
blisters because fingernails may carry germs that could cause an infection.
The rash will only occur where urushiol has touched the skin; it doesn't spread throughout the body.
However, the rash may seem to spread if it appears over time instead of all at once. This is either
because the urushiol is absorbed at different rates in different parts of the body or because of repeated
exposure to contaminated objects or urushiol trapped under the fingernails.
The rash, blisters and itch normally disappear in 14 to 20 days without any treatment. But few can
handle the itch without some relief. For mild cases, wet compresses or soaking in cool water may be
effective. Oral antihistamines can also relieve itching.
FDA also considers over-the-counter topical corticosteroids (commonly called hydrocortisone's under
brand names such as Cortaid and Lanacort) safe and effective for temporary relief of itching associated
with poison ivy.
For severe cases, prescription topical corticosteroid drugs can halt the reaction, but only if treatment
begins within a few hours of exposure. "After the blisters form, the [topical] steroid isn't going
to do much," says Epstein. The American Academy of Dermatology recommends that people who have had
severe reactions in the past should contact a dermatologist as soon as possible after a new exposure.
Severe reactions can be treated with prescription oral corticosteroids. Phillip M. Williford, M.D.,
assistant professor of dermatology, Wake Forest University, prescribes oral corticosteroids if the
rash is on the face, genitals, or covers more than 30% of the body. The drug must be taken for
at least 14 days, and preferably over a three-week period, says FDA's Ko. Shorter courses of treatment,
he warns, will cause a rebound with an even more severe rash.
There are a number of OTC products to help dry up the oozing blisters, including:
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aluminum acetate (Burrows solution)
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baking soda
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Aveeno (oatmeal bath)
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aluminum hydroxide gel
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calamine
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kaolin
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zinc acetate
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zinc carbonate
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zinc oxide
Desensitization, vaccines, and barrier creams have been studied over the last several decades for
their potential to protect against poison ivy reactions, but none have been approved by FDA for this
purpose.