Wondering about cast care? Get the answers to common cast care questions, from keeping a cast clean and reducing swelling to knowing when to call the doctor. By Mayo Clinic Staff

If your child breaks a bone, a cast can help support and protect the injury as it heals. Without proper care, however, a cast can't do its job. Understand the basics of cast care and how a cast can promote your child's recovery.

Casts are custom-made to fit and support injured limbs. There are two main types of casts:

  • Fiberglass casts. Fiberglass is a type of plastic that can be shaped. Fiberglass casts are typically lighter and more durable than traditional plaster casts. Air circulates more freely inside a fiberglass cast. Also, X-rays penetrate fiberglass casts better than plaster casts. This is helpful if your child's doctor wants to use an X-ray to examine your child's bones while he or she is still wearing the cast. Fiberglass casts are available in different colors.
  • Plaster casts. Plaster casts are easier to mold for some uses than are fiberglass casts. Also, plaster casts are typically less expensive than fiberglass casts.

Swelling can cause your child's cast to feel tight and uncomfortable. To reduce swelling:

  • Elevate the affected area. For the first 24 to 72 hours after your child's cast is applied, use pillows to raise the cast above the level of your child's heart. If possible, try to keep the cast raised even while your child is asleep.
  • Keep moving. Encourage your child to frequently move the fingers or toes of his or her injured limb.
  • Apply ice. For the first 48 to 72 hours after your child's cast is applied, loosely wrap an ice pack covered in a thin towel around your child's cast. Apply ice to the cast — not the skin — for 20 minutes every two hours. If your child is asleep, there's no need to wake him or her to apply the ice.

A cast can cause your child's underlying skin to feel itchy. To relieve itchy skin:

  • Set a hair dryer on a cool setting and aim it under the cast
  • Apply an ice pack covered in a thin towel to the area
  • Ask your child's doctor about giving your child an over-the-counter antihistamine

Don't allow your child to stick objects, such as a coat hanger, inside the cast to scratch his or her skin. This could injure your child's skin and cause an infection.

It depends on the type of cast. For example:

  • Plaster casts are meant to stay dry. If your child has a plaster cast over cloth wrapping, do what you can to keep the cast dry. During daily bathing, consider covering your child's cast in a plastic bag, taping the bag shut and keeping the cast outside of the shower or tub — or using another type of waterproof shield.
  • Fiberglass casts can usually get wet. If your child has a fiberglass cast that's lined with a water-repellent liner, it's OK for him or her to get the cast wet — as long as you have the doctor's OK. If your child swims with the cast, thoroughly rinse the inside of the cast with clean water afterward. Generally, you can allow the cast to air-dry. Keep in mind, though, that even a fiberglass cast can become uncomfortable and irritate your child's skin when wet. As with a plaster cast, consider covering your child's fiberglass cast in plastic or using a waterproof shield during daily bathing.

To dry any type of cast, use a hair dryer on a cool setting. Don't use a warm or hot setting, which could burn your child's skin. You might also use a vacuum cleaner hose to pull air through the cast and speed up the drying process.

You and your child can take steps to keep his or her cast in good condition. For example:

  • Keep it clean. Keep dirt and sand away from the inside of your child's cast. Cover your child's cast while he or she is eating.
  • Skip lotions. Avoid placing powder, lotion or deodorant on or near the cast.
  • Leave adjustments to your child's doctor. Don't pull the padding out of your child's cast. Don't trim the cast or break off rough edges without first asking your child's doctor.

Contact your child's doctor immediately if:

  • Your child's skin becomes red or raw around the cast
  • Your child feels increasing pain and tightness in the injured limb
  • Your child feels numbness or tingling in the injured hand or foot
  • Your child feels burning or stinging under the cast
  • Your child develops excessive swelling below the cast
  • Your child can't move the toes or fingers of his or her injured limb or they become blue or cold
  • The cast develops a crack, soft spots, a foul odor or becomes soaking wet and doesn't dry after use of a hair dryer or vacuum cleaner hose
  • The cast feels too tight or too loose

Caring for a child's cast isn't always easy. Remind your child that taking care of his or her cast will help minimize discomfort during the healing process — and that the cast will be ready to come off before he or she knows it.

Apr. 28, 2012