A cast can't do its job without proper care. Find out the basics of cast care, from keeping a cast clean 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. But a cast can't do its job without proper care. Find out more about the basics of cast care.

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

  • Plaster casts. Plaster casts are easier to mold for some uses than are fiberglass casts. Plaster casts are also generally less expensive.
  • Fiberglass casts. These plastic casts are typically lighter and more durable than plaster casts. Also, X-rays penetrate fiberglass casts better than plaster casts — making it easier for your doctor to examine your child's bones while he or she is still wearing the cast.

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. Your child will need to recline if the cast is on a leg.
  • Apply ice. Loosely wrap an ice pack covered in a thin towel around your child's cast at the level of the injury. Wrapping the ice is important to keep the cast dry. Ice that's packed in a rigid container and touches the cast at only one point won't be as effective.
  • Keep moving. Encourage your child to frequently move the fingers or toes of the injured limb.

A cast can cause your child's underlying skin to feel itchy. To relieve itchy skin, turn a hair dryer on a cool setting and aim it under the cast.

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

That depends on the type of cast your child has. In general, casts are meant to stay dry. A wet cast can lead to skin irritation or infection.

Plaster casts and fiberglass casts with conventional padding aren't waterproof. Keep your child's cast dry during baths or showers by covering it with two layers of plastic, sealed with a rubber band or duct tape. Avoid swimming while wearing a cast that isn't waterproof.

A fiberglass cast that has a waterproof liner can get wet. Only certain types of breaks can be treated with a waterproof cast and liner. Ask your doctor if it's safe for your child to get his or her cast wet.

If the cast does get wet, you might be able to dry out the inside padding with a hair dryer. Use a low heat setting to avoid burning or irritating the skin.

Try these tips:

  • Keep it clean. Keep dirt and sand away from the inside of your child's cast.
  • Skip toiletries. 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:

  • Feels increasing pain and tightness in the injured limb
  • Feels numbness or tingling in the injured hand or foot
  • Feels burning or stinging under the cast
  • Develops excessive swelling below the cast
  • Can't move the toes or fingers of his or her injured limb, or they become blue or cold
  • Says the cast feels too tight or too loose
  • Develops red or raw skin around the cast
  • Develops a crack, soft spots or a foul odor in the cast, or gets the cast soaking wet and doesn't dry it properly

Caring for a child's cast isn't always easy. Remind your child that taking care of the cast will help minimize discomfort during the healing process.

April 13, 2018