Heading outdoors to enjoy the warmer weather? You may get some unwanted company during snake season – the number of rattlesnakes being seen on Arizona trails seems to be picking up.

Getting bit by a rattlesnake can be fatal and cause a great deal of pain, says Meghan Spyres, MD, a toxicologist with Banner Poison and Drug Information Center. The center has already helped care for one rattlesnake-bite patient this year.

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“So, if you see a snake while hiking, you definitely want to stop, maybe take a couple steps back, give it some space, and then go around it,’’ she said. “And when you do that, make sure you’re also looking for any other snakes that might be out there.’’

Rattlesnake venom affects people in two ways, Spyres said.

It can cause pain, swelling, redness, bruising, and even tissue necrosis at the site of the bite. Rattlesnake venom also impairs your ability to clot blood.

“It’s uncommon to die from a rattlesnake bite, but it certainly can occur,’’ she said. “They (severe bites) can cause your whole body to kind of have a reaction. Your blood pressure can go low. And that’s one of the reasons it’s important to seek immediate medical care, especially in the cases that might be more severe.’’

If you are bitten, call 911 immediately, remove any tight jewelry, elevate the bite site, she said.

If you are bitten, there are also actions that shouldn’t take, including:

• Don’t apply tourniquets: Stopping blood flow may help with other types of snake bites but not with rattlesnakes, Spyres said.

• Don’t try to suck out the wound: “That’s not effective. And in fact, I’ve seen complications from people trying to suck out the venom that cause infections in the wound.’’

• Don’t capture the snake: Toxicologists can treat snakebite patients without knowing the type they encountered.