Topic Overview
What are poison ivy, oak, and sumac?
Poison ivy,
poison oak, and poison sumac are plants that can cause a skin rash called
allergic contact dermatitis when they touch your skin. The red,
uncomfortable, and itchy rash often shows up in lines or streaks and is marked
by fluid-filled bumps (blisters) or large raised areas (hives). It is the most common skin problem caused by
contact with plants (plant dermatitis).
See a picture of
poison ivy, oak, and sumac leaves.
What causes a poison ivy, oak, or sumac rash?
The
rash is caused by contact with an oil (urushiol) found in poison ivy, oak, or
sumac. The oil is present in all parts of the plants, including the leaves,
stems, flowers, berries, and roots. Urushiol is an
allergen, so the rash is actually an
allergic reaction to the oil in these plants. Indirect
contact with urushiol can also cause the rash. This may happen when you touch
clothing, pet fur, sporting gear, gardening tools, or other objects that have
come in contact with one of these plants. But urushiol does not cause a rash on
everyone who gets it on his or her skin.
What are the symptoms of the rash?
The usual
symptoms of the rash are:
- Itchy skin where the plant touched your
skin.
- Red streaks or general redness where the plant brushed
against the skin.
- Small bumps or larger raised areas
(hives).
- Blisters filled with fluid that may leak out.
The rash usually appears 8 to 48 hours after your
contact with the urushiol. But it can occur from 5 hours to 15 days after
touching the plant.1 The rash usually takes more than
a week to show up the first time you get urushiol on your skin. But the rash
develops much more quickly (within 1 to 2 days) after later contacts. The rash
will continue to develop in new areas over several days but only on the parts
of your skin that had contact with the urushiol or those parts where the
urushiol was spread by touching.
The rash is not contagious. You
cannot catch or spread a rash after it appears, even if you touch it or the
blister fluid, because the urushiol will already be absorbed or washed off the
skin. The rash may seem to be spreading. But either it is still developing from
earlier contact or you have touched something that still has urushiol on
it.
The more urushiol you come in contact with, the more severe
your skin reaction. Severe reactions to smaller amounts of urushiol also may
occur in people who are highly sensitive to urushiol. Serious symptoms may
include:
- Swelling of the face, mouth, neck, genitals,
or eyelids (which may prevent the eyes from opening).
- Widespread,
large blisters that ooze large amounts of fluid.
Without treatment, the rash usually lasts about 10 days
to 3 weeks. But in people who are very sensitive to urushiol, the rash may take
up to 6 weeks to heal.
How is the rash diagnosed?
The rash usually is
diagnosed during a physical exam. Your doctor will examine
the rash and ask questions to find out when you were exposed to the plant and
how long it took the rash to develop. If you are not sure whether you were
exposed to a plant, he or she will ask about your outdoor activities, work, and
hobbies.
How is the rash treated?
Most poison ivy, oak, or
sumac rashes can be treated successfully at home. Initial treatment consists of
washing the area with water immediately after contact with the plants. To
relieve symptoms, use wet compresses and take cool baths. Nonprescription
antihistamines and calamine lotion also may help
relieve symptoms. Moderate or severe cases of the rash may require treatment by
a doctor, who may prescribe
corticosteroid pills, creams, ointments, or shots
(injections).
How can I prevent the rash from poison ivy, oak, and sumac?
The best way to prevent the rash is to learn to identify
and avoid the plants. When you cannot avoid contact with the plants, heavy
clothing (long pants, long-sleeved shirt, and vinyl gloves) and barrier creams
or lotions may help protect you.
Frequently Asked Questions
Learning about poison ivy, oak, and sumac: | - What are poison ivy, oak, and sumac?
- What causes a poison ivy, oak, or sumac rash?
- Can I prevent the poison ivy, oak, or sumac rash?
- What are the symptoms of a poison ivy, oak, or sumac rash?
- What happens in a poison ivy, oak, or sumac rash?
- What increases my risk for getting a poison ivy, oak, or sumac rash?
- Where are poison ivy, oak, and sumac found, and what do they look like?
- Can other plants cause a rash?
- What other types of rash may look like poison ivy, oak, or sumac rash?
|
Being diagnosed: | |
Getting treatment: | |
Living with poison ivy, oak, and sumac rash: | |
Cause
Contact with
poison ivy, oak, or sumac plants can cause a rash
(allergic contact dermatitis). The rash is caused by contact
with the oil (urushiol) in these plants. Urushiol is an
allergen, so the rash is actually an
allergic reaction to the oil in poison ivy, oak, or
sumac.
- The leaves, stems, vines, twigs, berries, and
roots of these three plants contain urushiol, even after they have
died.
- Urushiol is a colorless, odorless, sticky oil that is easily
spread before a rash develops.
- The rash can also occur after
indirect contact with this oil. This may happen when
you touch clothing, pet fur, sporting gear, gardening tools, or other objects
that have come in contact with one of these plants.
No one is born allergic to any of these plants. You become
allergic to them through contact with them (or with
other plants). After you have been in contact with one
of the plants one or more times, your body's immune system may recognize
urushiol as an allergen and you may have an allergic reaction. You may be
more or less sensitive than other people to the plants. A more sensitive
person will react after contact with only a small amount of urushiol and have a
more severe reaction.
Symptoms
The most common symptoms of the rash
(allergic contact dermatitis) from
poison ivy, oak, or sumac are:
- Itching.
- Red streaks or general
redness where the plant brushed against the skin.
- Small bumps or
larger raised areas (hives).
- Blisters filled with fluid that
may leak out. In rare cases, some people develop blood-filled blisters that can
turn black and become shiny dark spots.
The rash may have several stages, and its severity can also
vary. It usually appears 8 to 48 hours after you have contact with the plant
oil (urushiol). But it may occur up to 15 days after the contact.1 The rash will continue to develop in new areas over several
days but only on the parts of the skin that first had contact with the plant
oil or those parts where the oil was spread by touching. Blister fluid cannot
spread the rash. Areas where the skin is thick, such as the soles of the feet
and the palms of the hands, are less sensitive to the oil.
People
who are highly allergic to the urushiol in these plants can have more
serious symptoms that may need medical treatment. Serious symptoms may
include:
- Swelling of the face, mouth, neck, genitals, or
eyelids (which may prevent the eyes from opening).
- Widespread,
large blisters that ooze large amounts of fluid.
Other conditions with similar symptoms
Other kinds
of plant rashes can look like a poison ivy, oak, or sumac rash. These include
rashes caused by:
- Other plants, such as the ginkgo tree,
which contain urushiol or a similar oil.
- Irritant plants, such as stinging nettle. These rashes are not caused by allergic
reactions.
- Phytophotodermatitis, which may happen when you touch
certain plants and then go into the sun.
Skin conditions that may look like the rash from poison
ivy, oak, or sumac include:
- Scabies, an
itchy skin condition caused by mites.
- Shingles
(herpes zoster), a viral skin infection.
- Impetigo, a
bacterial infection of the skin.
Insect bites, exposure to nickel and other metals, and
exposure to chemicals found in fabrics, lotions, or laundry detergent may also
result in a similar skin rash.
What Happens
Contact with
poison ivy, oak, or sumac can cause a rash (allergic
contact dermatitis). The rash is caused by contact with the oil (urushiol) in
these plants. Urushiol is an
allergen, so the rash is actually an
allergic reaction to the oil in these plants.
Normally, the
immune system protects the body from viruses and
bacteria by producing
antibodies to fight them. In an allergic reaction, the
immune system overreacts and starts fighting essentially harmless substances as
though these substances were trying to attack the body. This overreaction
causes problems that affect the skin, nose, lungs, digestive organs, and blood
vessels. In the case of contact with poison ivy, oak, or sumac, it results in a
rash.
You are not allergic to these plants until contact with
urushiol triggers a reaction. The contact with urushiol can either be direct or
indirect, such as through clothes, tools, or other
objects.
Most poison ivy, oak, and sumac rashes develop within 8
to 48 hours after touching urushiol, but they can take as long as 15 days to
form.2, 1 The rash usually
takes more than a week to show up the first time you get urushiol on your skin.
But the rash develops much more quickly (in 1 to 2 days) after later
contacts. The rash usually lasts 10 days to 3 weeks, but more severe cases
can last up to 6 weeks.1 After the rash heals, there
are usually no permanent scars on the skin.
The rash is not
contagious. You cannot catch or spread the rash after it appears, even if you
touch it or the blister fluid, because the urushiol will already be absorbed
into or washed off the skin. Sometimes people mistakenly believe that the rash
is spreading because it appears later on different parts of the body. But the
rash only appears where urushiol has come in contact with the skin. So either
the rash is still developing from earlier contact, or you have touched something
that still has urushiol on it.
How
sensitive you are to poison ivy, oak, or sumac and how bad your reaction is depend primarily on your age and on the extent of the
first contact or first few contacts with the plant. Other influences include
physical activity and immune system function. Some
studies show that how allergic you are to the plants may be inherited.1
Complications
Complications from a poison ivy,
oak, or sumac rash usually do not occur in healthy people.
- The rash can occur all over the body
(generalized eruption) in highly allergic people.
- Excessive
scratching of the rash may discolor the skin or cause a bacterial
infection.
- The rash may come back or get worse if treatment ends
too soon or if the medicine used is not strong enough.
- In rare
cases, kidney problems (nephrotic syndrome) can occur. This can
happen in any severe allergic reaction and is not specific to poison ivy, oak,
or sumac.
What Increases Your Risk
People in certain jobs or
with outdoor hobbies have an increased risk for contact with
poison ivy, oak, or sumac and the resulting rash
(allergic contact dermatitis). These people include:
- Landscapers.
- Forest firefighters
and forestry workers.
- Electrical linemen.
- People who
install fences.
- Maintenance workers in parks, gardens, and
nurseries.
- Hikers, campers, rafters, kayakers, and fishermen.
Your risk of having a reaction to poison ivy, oak, or sumac and the
severity of your
allergic reaction depend mainly on your age and on the
extent of the first contact or first few contacts with the plant. Other
influences include physical activity and immune system function.
Some studies show that how allergic you are to the plants may be
inherited.1
When To Call a Doctor
Call 911 or other emergency services if you have a rash and:
- Are having severe trouble breathing.
Call a doctor
if:
- The rash (allergic
contact dermatitis) from
poison ivy, oak, or sumac causes great discomfort that
is not relieved by home treatment (for instance, you apply calamine lotion to
the rash, but itching continues to make it difficult to sleep).
- The
rash shows
signs of infection, such as pain, swelling, or warmth
around the affected area.
- The rash covers a very large area of the
body.
- Home treatment causes the rash to get worse or to come back
after nearly disappearing.
- Rashes occur frequently, and you are not
sure what is causing them. (The rashes may be caused by another kind of
plant.)
- Your mouth is swollen or you think the rash has spread to your
mouth.
- The rash has spread to your face, particularly around an
eye.
- You have a rash and a
weakened immune system.
Watchful waiting
Watchful waiting is a wait-and-see approach. If
the rash is not severe, watchful waiting may be appropriate. Home treatment may
be used to relieve symptoms. Dark spots may develop, but this is not
serious.
Watchful waiting is not appropriate if the rash develops
over your entire body, becomes infected, or reappears or gets worse after using
medicine. See your doctor.
Who to see
You may not
need to see a doctor for the rash. But if you want to find the
cause of the rash or if you want to treat an uncomfortable, severe, or infected rash, you may
choose to see:
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Exams and Tests
A rash (allergic
contact dermatitis) from
poison ivy, oak, or sumac plants usually is diagnosed
through a physical exam and questions about your outdoor activities.
Your doctor will examine the rash to decide which kind of plant
caused it and ask about:
- The length of time between possible exposure
and development of the rash.
- The length of time you were out in the
sun.
- What you were doing when the exposure may have occurred
(hiking, for example).
- Other rashes you have had.
- Your
job and your hobbies.
Diagnosis is harder when there are no clues that you have
been in contact with the plant. Sometimes
indirect contact with the plant oil (urushiol) causes
the rash. Urushiol that is on clothing or other objects may spread to your skin
months after initial contact. If a bacterial infection is suspected, your
doctor may take a sample of blister fluid for a
culture.
If your primary care doctor is
not sure of the cause, you may need to see a
dermatologist for a direct patch skin test. In this
test, small amounts of allergens are placed on the skin and covered with a
bandage for several days. The patch is then removed and the skin is examined for
reactions.
Treatment Overview
The rash (allergic
contact dermatitis) from
poison ivy, oak, or sumac generally is mild and can be
treated at home. Home treatment for the rash usually helps relieve symptoms but
does not speed up healing of the rash.
- If you know you had contact with one of these
plants,
immediately wash areas of the skin that may have
touched the plant. Sometimes the rash can be completely avoided by washing the
affected areas with plenty of water within 10 or 15 minutes of contact. You
could also try using a product (such as Tecnu or Zanfel) that is designed to
remove the oil from your skin.
- To relieve itching and help dry blisters, apply wet compresses or soak the
area in cool water. Antihistamine pills or calamine lotion may help relieve
symptoms.
- If you have a moderate to severe rash, you may need to
see your doctor. He or she may prescribe
corticosteroid pills. These medicines may help improve
or clear up the rash more quickly. Prescription corticosteroid creams,
ointments, gels, or shots may also be used.
A frequent complication of the rash is
infection. If this occurs, your doctor
will probably prescribe an
antibiotic cream that you spread on the affected skin
if the infection is small. Otherwise, you may need antibiotic pills or a
shot. To prevent infection, try not to scratch the rash. Cut your fingernails
short to minimize the possibility of opening the skin and spreading
bacteria.
Regardless of what type of treatment is used after a
rash develops, the length of time it lasts will vary from person to
person.
Prevention
Only the oil (urushiol) from
poison ivy, oak, or sumac plants can cause a rash
(allergic contact dermatitis). The best way to avoid contact
with urushiol and getting a rash is to avoid the plants.
- Learn to
recognize these plants, especially those near where
you live. The plants may look different depending on the season and the area
where they are growing. A county agricultural extension service may be able to
help you identify the plants in your area. See a picture of
poison ivy, oak, and sumac leaves.
- Even though their appearance changes
with the seasons, the plants usually contain the same amount of urushiol
year-round, even in the winter when they only appear as bare sticks. Black
areas on the plants may help you identify them in the winter (urushiol turns
black when exposed to air). Living, dormant, and dead plants all contain
urushiol, although dead leaves do not contain a lot of it.
-
You may also try to
remove the plants when appropriate. Never handle these
plants without vinyl gloves (urushiol can penetrate rubber).
- When
you cannot avoid being near poison ivy, heavy clothing (long pants, long
sleeves, enclosed footwear) may help prevent the oil from touching your skin.
Clothing or any other object that has touched the plant must be handled
carefully and washed thoroughly.
- If you are often in areas where
poison ivy, oak, or sumac grows, you may want to get a product (such as Tecnu
or Zanfel) that is designed to remove the plant oil (urushiol) from your
skin.
- Barrier creams and lotions can be used to prevent
urushiol from contacting the skin or to reduce the severity of a reaction.
These creams vary in their potency and are not always effective.
If you suspect that your skin has touched poison ivy, oak,
or sumac, wash the area to
help prevent a reaction. Clothing and other items that may have oil on them should be thoroughly washed
right away too.
Home Treatment
The rash (allergic
contact dermatitis) from
poison ivy, oak, or sumac typically is mild and can be
treated at home. Home treatment for the rash usually helps relieve symptoms
rather than speeding up the time it takes the rash to heal.
- If you know you had contact with one of the
plants,
immediately wash areas of the skin that may have
touched the plant. Sometimes the rash can be completely avoided by washing the
affected areas with plenty of water. Clothing and other items that may have oil on them should be thoroughly washed right away too.
- To relieve itching and help blisters dry out, apply wet compresses or soak
the area in cool water.
Antihistamine pills or calamine lotion may help
relieve symptoms.
- To prevent infection, try not to
scratch the rash. Also, cut your fingernails short to minimize the possibility
of opening the skin and spreading bacteria.
Medications
Antihistamine pills are used to relieve
the symptoms of the rash from
poison ivy, oak, or sumac. Prescription medicines,
such as corticosteroids, may be used for severe rashes. Medicines are also used
to make the rash less severe.
Medication Choices
- Antihistamine pills can help
relieve itching and dry blisters. Examples include
Benadryl (diphenhydramine), which is an over-the-counter
medicine, and Vistaril (hydroxyzine), which you get by
prescription.
- Corticosteroids may be used to treat a moderate
or severe rash. Corticosteroids may be given as pills, products that are spread on the skin (creams, ointments, gels), or shots.
- Barrier creams and lotions help prevent the plant oil
(urushiol) from coming in contact with the skin or reduce the severity of a
reaction. These creams vary in their potency and are not always
effective.
You may be able to use a product that dissolves
urushiol, such as Tecnu or Zanfel. These products are used to wash the oil off your skin or other objects. They may reduce the severity of a reaction or prevent one.
The most common
complication of poison ivy, oak, or sumac rash is a secondary
infection, usually caused by scratching. When this
occurs, your doctor will probably prescribe a type of topical
antibiotic cream if the infection is in a small area.
Otherwise, you may need systemic antibiotics, given as pills or
shots.
What To Think About
The following medicines should
not be used for poison ivy, oak, or sumac rash, because they can cause allergy
problems of their own:
- Antihistamines applied to the skin, such as diphenhydramine (found in Benadryl cream,
spray, or gel).
- Anesthetics applied to the skin
containing benzocaine (such as Lanacane).
- Antibiotics containing neomycin (such as
Neosporin or Poly-Pred).
Surgery
There are no surgical treatments for a
poison ivy, oak, or sumac rash.
Other Treatment
Creating tolerance and reducing sensitivity
Some cultures, including
certain Native American cultures, have used
homeopathic treatment for
poison ivy, oak, or sumac as a means of preventing the
rash. Stories of successful prevention of rash through eating the
leaves are common, but research studies have failed to reproduce these results
without the people involved in the studies developing mild to serious side
effects.
Other Places To Get Help
Organizations
| National Institute for Occupational Safety and Health
(NIOSH) |
| 395 E Street SW |
| Suite 9200 |
| Washington, DC 20201 |
| Phone: | 1-800-CDC-INFO (1-800-232-4636)
(513) 533-8328 (outside the U.S.) |
| Fax: | (513) 533-8347 |
| Email: | cdcinfo@cdc.gov |
| Web Address: | www.cdc.gov/niosh |
| |
The National Institute for Occupational Safety and
Health (NIOSH) conducts research and makes recommendations for the prevention
of work-related injuries and illnesses. NIOSH also provides information to the
public. |
|
| American Academy of Dermatology |
| P.O. Box 4014 |
| Schaumburg, IL 60168 |
| Phone: | 1-866-503-SKIN (1-866-503-7546) toll-free
(847) 240-1280 |
| Fax: | (847) 240-1859 |
| Email: | MRC@aad.org |
| Web Address: | www.aad.org |
| |
The American Academy of Dermatology (AAD) provides information
about the care of skin. You can locate a dermatologist in your
area by using their "Find a Dermatologist" tool. Or you can read the latest news in dermatology. "SPOT Skin Cancer" is the AAD's program to reduce deaths from melanoma. There is also a link called "Skin Conditions" that has information about many common skin problems. |
|
| KidsHealth for Parents, Children, and
Teens |
| Nemours Home Office |
| 10140 Centurion Parkway |
| Jacksonville, FL 32256 |
| Phone: | (904) 697-4100 |
| Web Address: | www.kidshealth.org |
| |
This website is sponsored by the Nemours Foundation. It
has a wide range of information about children's health, from allergies and
diseases to normal growth and development (birth to adolescence). This website
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly emails about your area of interest. |
|
References
Citations
- Gladman AC (2006). Toxicodendron dermatitis: Poison ivy, oak, and sumac.
Wilderness and Environmental Medicine, 17(2):
120–128.
- Anderson BE, Marks JG Jr (2007). Plant-induced
dermatitis. In PS Auerbach, ed., Wilderness Medicine,
5th ed., pp. 1262–1286. Philadelphia: Mosby Elsevier.
Other Works Consulted
- Anderson BE, Marks JG Jr (2007). Plant-induced
dermatitis. In PS Auerbach, ed., Wilderness Medicine,
5th ed., pp. 1262–1286. Philadelphia: Mosby Elsevier.
- Gladman AC (2006). Toxicodendron dermatitis: Poison ivy, oak, and sumac.
Wilderness and Environmental Medicine, 17(2):
120–128.
- Hall JC (2010). Contact dermatitis section of Dermatologic allery. In JC Hall, ed., Sauer's Manual of Skin Diseases, 10th ed., pp. 78–84. Philadelphia: Lippincott Williams and Wilkins.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | William H. Blahd, Jr., MD, FACEP - Emergency Medicine |
|---|
| Specialist Medical Reviewer | H. Michael O'Connor, MD - Emergency Medicine |
|---|
| Last Revised | August 30, 2011 |
|---|