Your daughter goes rollerblading and twists her ankle pretty badly. A misstep off the curb, and your wrist takes the brunt of the fall. An injured limb can cause intense pain. But how can you tell if the injury is serious enough to warrant a trip to the ER — or if you’re better off popping a pain reliever and taking a wait-and-see approach?

For a lot of people, the knee-jerk reaction is to rush to the ER. But if you’re not dealing with a break, emergency room docs say that heading to the ER can be a waste of time and money, not to mention unnecessary X-rays. A sprain, which involves the straining or tearing of a ligament (fibrous tissue that connects two bones and supports a joint), doesn’t require emergency medical attention. But depending on the severity of the sprain, you may need to see a physician or orthopedist, or go to an urgent care center.

Learn the signs that signal a fracture or sprain, and follow these simple guidelines for treatment.

When to head to the ER

The obvious signs that you have a fracture and need to head to the ER right away: The bone is deformed, protruding into the skin or breaking through it. “In the case of deformity or if a bone is protruding, you run risk of an infection, or damaging blood vessels or nerves and risking long-term complications, if you don’t get it looked at immediately,” says Seth Podolsky, MD, emergency medicine physician at the Cleveland Clinic.

Head to the ER immediately if the injured person shows any of these signs — even if the bone doesn’t look obviously broken:

  • Loss of function. The injured limb or joint can’t be moved; a foot or leg can’t hold weight.
  • Discoloration. Blue, black or green bruising can occur when a broken bone damages the surrounding blood vessels (a sprain can also cause bruising).
  • Tingling, numbness, pale or cold skin. The broken bone could be pressing on a nerve or could have severed a nerve.
  • The affected area is hot and inflamed, or you have a fever. All of these reactions signal infection.

What happens at the ER

If the ER doctor can’t determine from the physical exam whether there’s a fracture or a sprain, she’ll recommend an X-ray. If the fracture is a simple break, the ER doc will immobilize the area with a splint while the swelling goes down. You’ll then be instructed to see an orthopedist a few days later to have a cast put on. With more complex breaks, the bone will be realigned manually or may require surgery. Again, a cast won’t be put on until the swelling goes down.

If the bone isn’t broken, but there is a sprain, the doctor may still apply a splint or Ace bandage to help immobilize the area. “In my experience, you can have as much pain with a strain as with a break,” says Podolsky. Stabilizing the area helps prevent movement that can be painful and cause further injury. 

When an office visit makes sense

If emergency treatment isn’t needed, but the pain persists despite taking an over-the-counter pain reliever and/or there’s lots of swelling (without the more serious symptoms mentioned above), you’re likely dealing with a sprain. A pediatrician, general practitioner or orthopedist can determine the level of injury. Based on this, the doctor may recommend no sports/exercise or limited activity until the injury has fully healed. A soft brace or an Ace bandage over a splint may be applied.The location and severity of the sprain will determine how long it takes to heal, which could be anywhere from two weeks to three months. 

Laurie Tarkan is an award-winning health journalist for the New York Times, national consumer magazines and websites.