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Wednesday, November 23, 2011

POISON IVY and POISON OAK - A Concise Summary of Diagnosis and Treatment

Author
Adam Goldstein, MD, MPH
Physician
Chapel Hill, NC

Most people in the U.S. have either gotten poison ivy or poison oak at one point in time, or they know someone who has gotten it. Poison ivy and poison oak cause tremendous misery to those who get it and to their family members who endure their loved one’s itching. Even doctors often fail to recognize the severity of the condition, resulting in needless delays in diagnosis and effective treatment. Finally, many beliefs exist about poison ivy, such as that scratching makes it spread or that it is contagious, most of which are wrong!

The purpose of this article is to give accurate information about poison ivy and poison oak, their causes and treatment, for parents and other adults with a need to know what to do and what not to do about someone they know with poison ivy or poison oak.

WHAT EXACTLY ARE POISON IVY AND POISON OAK?
Both poison ivy and poison oak come from the plant family called Toxicodendron. The plants contain a chemical poison called urushiol that is highly irritating to human skin. The condition that poison ivy and poison oak cause is called “allergic contact dermatitis.” It’s called allergic because the plant causes the skin to become severely inflamed and itch. You cannot get it unless you actually come in contact with the poison. Dermatitis means severe reaction or inflammation (-itis) in the layer of the skin called the dermis. In other words, these types of toxic or skin poisons cause an allergic skin reaction when you come in contact with them.


WHAT IS THE DIFFERENCE BETWEEN POISON IVY, POISON OAK, AND POISON SUMAC?
Actually, very little difference exists between all forms of poison ivy and poison oak. The difference comes from the slightly different type of Toxicodendron plant family each comes from. Poison sumac is another form of Toxicodendron plant family that causes an allergic contact dermatitis. All forms of this family have similar symptoms and are treated virtually the same.

WHO GETS POISON IVY AND POISON OAK?
The simple answer is almost everyone. Up to 75% of people who come in contact with the leaves, vines, or oil from the plant will have a skin reaction. Each year in the U.S. alone, tens of millions adults and children get poison ivy or poison oak. It is found in almost every state (at altitudes less than 4000 feet and in places that receive at least several inches of rain each year).

While it is true that some individuals will not get poison ivy or poison oak when they come into contact with the plant, most will. After repeated exposure, most will get skin irritation even more easily, because the skin becomes highly sensitive to the poison. People who go outside and work in gardens, who have outdoor occupations, and who take hikes in the woods are particularly likely to get poison ivy. Although people are much more likely to get poison ivy and poison oak during the summer months, cases can occur at any time of year if someone comes into contact with the plants.

HOW EXACTLY DO YOU “GET” POISON IVY AND POISON OAK?
The way most everyone gets poison ivy or poison oak is by touching the plant itself (see figure A below). Some people get confused with plants like the 'Virginia Creeper' that look similar to poison ivy and poison oak, but they have five leaves, not three, and are harmless when touched (See Figure B below). Since most people actually touch the plants while hiking or gardening, the chemical poison in the plants affects them everywhere the plant has touched them. If they touched the plant with their hands, they will get poison ivy on their hands. If the plant touched their legs and thighs while hiking, they will get the disease on their legs and thighs. If they are sweating, and they wipe their face and neck with their hands that have just touched the plant, they will likely get poison ivy on their face and neck. More rarely, people can get a severe case of poison ivy all over their body or face by exposure to the “fumes” when the plant is burned.


WHAT ARE THE SYMPTOMS OF POISON IVY AND POISON OAK?
Almost everyone who has ever gotten poison ivy or poison oak can tell a doctor that their symptoms are itching, itching, and more itching. Frequently, the symptoms start out as very mild itching on a finger, hand, or forehead. You may not even see anything. You just start scratching or rubbing the skin. After a few hours or even a day, you notice that the skin where you have been rubbing and scratching is red and some small bumps are appearing. You also notice that several parts of the body seem to have the same thing happening.

The bumps of poison ivy and poison oak are usually small and red. At first, the bumps may appear isolated to different places of the body. Then they seem to come together into larger areas, often following “lines”, as if someone took a feather and drew it across the skin. This is in fact what has happened, as the leaf of the plant has drawn across the skin.

In fact, wherever the plant touched the skin, the rash will break out. Your skin, however, reacts at different times. This is important to know, because most people think that their poison ivy and oak are “spreading,” when in fact it is not. So, what may appear to you as spreading poison ivy is simply your skin reacting to the chemical poison at different times. The effect, however, is that you often cannot tell the full extent of poison ivy or poison oak simply by looking at what it looks like early on in the disease, in the first day or two. It will usually get worse. This is a really important piece of information to know, because your symptoms will also usually get worse.

As the condition gets worse, the small bumps come together and form groups of bumps called vesicles. These vesicles contain clear or honey-colored fluid with all kinds of cells that are reacting to the irritated skin. As you scratch more and more, the bumps and vesicles get more irritated and break open, forming crusts on the skin.

Often, people keep scratching these vesicles until they bleed. The reason is that the sensation of pain is less bothersome to most people than the symptoms of itching. Unfortunately, if you scratch your rash until it bleeds, it also means that you stand a chance of your rash getting infected with bacteria. In this case, you may need to take oral antibiotics. (See section on treatment below.)

HOW LONG WILL THE RASH LAST IF I DO NOTHING?
Most cases of poison ivy and poison oak will go away on their own within two or at most three weeks (See figure below). Some cases can last as long as a month. Many people do not recognize what the plant looks like, so they get repeated exposure and repeated outbreaks, particularly during the summer months.

HOW DO I KNOW IF I HAVE POISON IVY OR POISON OAK?
If you start itching in the summer, on several parts of your body, particularly your hands or arms or face, and then develop small red bumps that start to appear in streaky lines, with lots and lots of itching, then you may have poison ivy or poison oak, particularly if you were working or walking outdoors in the woods 1-2 days previously.

Many other diseases can look like poison ivy or poison oak initially, so it is not always easy to tell the difference, particularly early on in the process. Eczema (shownbelow) is a disease of dry skin that can cause itching over much of the body, but it is usually chronic and not acute. If poison ivy or poison oak occurs in someone who also has eczema, the skin irritation can be very great.


Poison ivy and poison oak can also look similar to some skin reactions to drugs. Allergies to other plants or even things like clothes, detergents, or latex, can have a similar appearance. Usually, allergies to most other items are symmetrical, that is, the rash looks fairly even on both sides of the body. In contrast, the rash of poison ivy and poison oak is usually not symmetrical, reflecting the rather chance locations that the plant has encountered the skin.

Finally, a disease called scabies, caused by a parasite, can also cause very severe itching of the skin, but it does not usually have vesicles that ooze fluid, and the distribution of scabies is often confined to the wrists, finger webs, underarms, waste, groin, ankles and toe webs.

IS POISON IVY OR POISON OAK CONTAGIOUS?
As mentioned earlier, you cannot get poison ivy from someone who has it, only from the exposure to the plant itself. Thus, if you touch someone else’s’ rash, you should not get the disease. Of course, why would you touch someone else’s rash, as it is their rash, not yours!

WILL I SPREAD POISON IVY ON MY BODY BY SCRATCHING IT?
The answer, as described above is no, no, and no. It may appear that way to you, but that is actually just where the plant originally touched your skin, and the skin reacts differently and at different times.

HOW DO I TREAT POISON IVY AND POISON OAK?
If you have poison ivy or poison oak limited to a small area, you can sometimes treat it by using creams that you can buy in your local drug store.

If the rash occurs on more than one arm and leg, if it occurs on your face, or if it causes you to scratch at all hours of the day or night, you probably want to talk to your doctor about getting a prescription medication called corticosteroids. You can get this medication as either a topical preparation to apply to your skin or pills you take by mouth.

Topical steroids prescribed by physicians come in many strengths, and you usually only need to apply them once or twice a day. They help but often times do not fully remove the itching, and once the full blown rash comes out, they are less effective.

For severe itching or disease that involves many parts of the body, doctors usually recommend oral corticosteroids, usually called prednisone. Prednisone is usually given at higher doses for the first several days and then the dose is lowered over 7-14 days. It is very important to take the prednisone pills exactly as your doctor directs. If you stop the prednisone too soon, the rash of poison ivy and poison oak will likely come back. Prednisone is highly effective in treating the rash and itching, and it can be taken usually only once a day.

Many over-the-counter lotions, creams, and ointments can help with itching. Some of these (Hytone, Cortaid, Cortisone, Aquanil HC, Dermtex) contain 0.5-1% hydrocortisone cream, a mild anti-inflammatory medication. Products that contain Calamine are soothing to the skin, and as they evaporate, the itch temporarily improves. Some products contain phenol, menthol, camphor or pramoxine that can ease itching temporarily. Brand names of these products include: Gold-Bond anti-itch cream, Tecnu rash relief spray, Calagel anti-itch gel, Pramoxine Anti-itch lotion, Dermoplast spray, Pramegel, Prax cream and lotion, Itch-X spray and gel, and Sarna cream and foam. Oatmeal baths, such as Aveeno, can also provide temporary relief.

Sometimes, an oral antihistamine (allergy pill), such as diphenhydramine, can also help lessen the itching. Topical antihistamines should be avoided however, as they can make the skin even more sensitive. You should ask your doctor about all these medications.

One of the best things you can do to ease the itching is put cold compresses on the rash. To do this, put a clean cloth in cool water, and then wring out the excess water. Burow’s solution is a medication (aluminum acetate) added to cool compresses that has a cooling and drying effect to decrease itching. One of the worst things you can do for the itching is to put heat on it, as this will simply cause it to become more irritated and itch more. You may notice that the itching worsens, for example, after you take a hot shower.

HOW CAN I AVOID GETTING POISON IVY OR OAK?
The best way to not get poison ivy and poison oak is to recognize the plant and avoid touching it if at all possible. The plants have a usual appearance as three-leaved groupings arising from a central red stem. Posion oak resembles leaves of an oak tree. The leaves of poison ivy are frequently quite shiny. An old rhyme is useful to remember: “Leaves of three, let it be”. Even when dried, the leaves can cause a rash if you touch them or the stem, so cutting down old poison ivy vines in the winter can still be problematic. If the leaves touch your pants, clothes, or gloves, make sure you wash the clothes or gloves thoroughly before wearing them again.

When hiking or gardening in areas with poison ivy, it is important to wear protective pants, long-sleeve shirt and even gloves. Do not burn poison ivy plants, as the fumes can cause a severe allergic reaction to those with sensitivity to the plant poison. Also, if you are hiking with a pet in an area with poison ivy, make sure you wash the pet after hiking to prevent the pet giving you the disease from exposure to the urushiol on the pet’s fur.

Some people who garden frequently in areas with lots of poison ivy may choose to use a product called IvyBlock, a lotion that contains Bentoquatam. This lotion may bind to urushiol and thus block the ability of urushiol to attach to the skin. It must be used at least 15 minutes before exposure to the plants, and it should not be used by children younger than seven years of age. It also must be reapplied after being exposed to the plants for more than four hours, and it leaves a clay-like residue on the skin after it dries.

Some people also consider using barrier creams that are about 60% effective in preventing poison ivy when applied liberally to the skin before being exposed. A study in 1992 from Duke University showed that products such as StokoGard barrier cream, Hollister Moisture Barrier cream or ointment, and Hydropel ointment are effective.

WHAT SHOULD I DO IF I TOUCH THE POISON IVY OR POISON OAK PLANT?
If you know that you have touched the plant and did not have gloves on, the very first thing you should do is immediately wash your hands with soap and water, or even wipe them down with rubbing alcohol followed by water. If you can do so within 5-10 minutes of exposure to the plant, you may be able to avoid getting the reaction. After 30 minutes, washing the skin is good, but you will likely still get the skin reaction and disease.

You can use several mild, over the counter detergent creams to cut down on the reaction you might get if you were not able to wash the skin in the first thirty minutes but you had significant exposure to poison ivy. One chemical that can decrease the reaction up to several hours after exposure is called Tecnu skin cleanser. You apply this cream for two minutes to places where you were exposed to the poison ivy or poison oak plant, and then wash with water. Goop hand cleaner in a gel, liquid or soap is another product designed to remove the oil resin from the skin. Finally, you can purchase a soap mixture of that combines ethoxlate and sodium lauroyl sarcosinate surfactants, called Zanfel, that can help remove urushiol in contact with the skin.

SHOULD I PUT BLEACH ON THE RASH?
Absolutely not! Using bleach on the skin is like putting a second poison on the skin. You will kill off several layers of skin, and your skin may hurt more than it itches for a while. Subsequently, you risk making the skin reaction much worse, including having infections of the skin.

CAN MY CHILD GO TO SCHOOL OR CAMP IF THEY HAVE POISON IVY OR POISON OAK?
Absolutely! Since poison ivy and poison oak are not contagious to others, no reason exists to keep children away from other children. Do not think, however, that teachers, school administrators or even other children will know all the information that you now know. You may need to educate them about the disease, or even get a doctor’s note saying that everything is okay.

WHAT ELSE DO I NEED TO KNOW?
If your rash does not get better, or if it worsens, you should see your doctor. It is also important to see your doctor if you develop a fever, if the rash covers a large area of your body, or if there is pus coming from the bumps on your skin. These symptoms may indicate that you need more than just over-the-counter treatments.

As mentioned above, sometimes other things can cause a severe itching rash, such as allergies to other substances. Your doctor can help determine what is causing the condition, and they will offer the best treatments available.



Source:

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