Doctors agree that the best way to prevent a case of poison ivy or poison oak is to be able to identify the plants and take precautions against making contact with them.

"Children should be taught in schools what poison ivy looks like in all seasons, and then be sternly warned to avoid it," said Dr. Mike Kolda, emergency services director at Southeast Missouri Hospital. "Then, if the kids pointed it out to their parents, we wouldn't have this problem."

Kolda and other area physicians see cases of poison ivy year-round, but more frequently in the spring and summer.

In the spring, poison ivy blooms with bright green leaves. As the plant matures during summer, the leaves are darker green, but are always in characteristic groups of three. As fall sets in and temperatures drop, the leaves turn a bright, crimson red. In the winter the leafless vines produce white berries.

In all seasons, the plant produces an oil that brushes off easily. When the oil comes into contact with human skin, most people develop an allergic reaction that begins in the form of a red, itchy rash, and can result in permanent scarring.

"The oil on the leaves, called urushiol, is the primary irritant," said Kolda. "Once that is washed from the skin, the irritation may run its course, but it can no longer be spread."

That rule holds true even when the blistering that typically follows the appearance of the rash bursts.

"Only the spread of the oil will cause the rash to spread," Kolda said. "Not anything else."

The oil can be spread from a pet's coat to a human hand, from exposed clothes in the laundry, and from person to person before it is washed from the skin.

"Most often it won't get better without medication," said Kolda. "In less-severe cases it will resolve itself, but it's going to itch some."

Several products -- both prescription and nonprescription drugs -- are available to relieve the itch. There is even a product that acts as a screen against the oil.

Jim Tillman, a pharmacist at Medical Arts Pharmacy, said the most typical products people use to alleviate the itch is Benedryl, Caladryl and other over-the-counter salves and solvents that have a drying, cooling effect on irritated skin.

There are drugs that can be taken orally, such as Benedryl alixer, that also will relieve the itch.

But for the most severe cases, doctors prescribe steroids for a short duration when the ivy itch is at its worst.

"Steroids by nature are anti-inflammants," said Tillman. "They have a drying effect on the ivy rash, but at the same time reduce the body's histamine release, thereby making the person feel better.

"The steroids are administered in declining dosage -- six the first day, five the next, and so on -- so they alleviate the symptoms, but don't harm the body's other functions," he said. "Steroids are only used when nothing else will work, and in the worst cases."

Some people who have more severe reactions to poison ivy are given desensitization injections in the early spring. Although the injections work for some, scientific studies show they are not as effective as those used on people with severe allergies.

Ivy Guard, a relatively new product, reduces by 85 percent the chances of developing the rash, if applied before contact with ivy oil.

"But you have to put it on before you are exposed," said Dr. Hal Brown, a dermatologist who is faced with a handful of severe cases of poison ivy and oak every year. "If you put the stuff on afterwards, it won't do a bit of good.

"You also have to wash all exposed skin with soap and water after you come in," he said. "Regular soap will do the trick. In any case -- with or without the Ivy Guard -- if you get the exposed area with soap and water within 10 minutes, you should be safe from infection."

Poison ivy and oak take a good two to three weeks to run their course. Depending upon the part of the body infected, the irritation can be minor, or so severe it requires medical attention.

"If you roast a hot dog on a poison ivy stick and ingest the oil, you could end up in the hospital," said Kolda. "Also, the rashes tend to be severe in areas like the face, under your arms and around the hands."

But the poison ivy oil will not develop into a rash on the eyes, the palms of your hands and the soles of your feet.

One of the best remedies for itching irritation that won't cost a cent is cool-water compresses.

"Warm water will make the itching worse every time," said Brown. "So, when you've got poison ivy, take the coolest showers you can stand. You'll feel better in the long run."

One of the dangers involved in poison ivy is the infection that can set in when blisters burst and are exposed to open air.

"If infection sets in, it could lead to extreme sickness and can cause extensive scarring," said Brown. "That is why the drying agents are important; they take the fluid out of the blisters without rupturing them."

Although there are several remedies to the problem, there are not universally excepted preventions from poison ivy.

"Stay away from it," said Brown. "It's more trouble than it's worth."

Causes of itching

Poison ivy

A woody rope-like vine or trailing shrub. The leaves grow in groups of three leaflets and have smooth or notched edges.

Poison oak

An upright shrub or small, tree-like plant. Like poison ivy its leaves also grow in groups of three.

Poison sumac

A shrub with pairs of seven to 13 leaflets arranged along a center rib with one single leaflet at the end.

Each plant can cause mild to intense burning and itching. The affected areas might feel hot or look swollen. Then they will begin to ooze and eventually dry and crust over.

You can have a reaction through direct or indirect contact with one of these plants. The juice of the plants stays active for months; so if garden tools, shoes, clothing, even your pet have been in contact, and you touch them, you can be affected.