What Is a Cast? A cast is a hard bandage that keeps part of the body from moving so it can heal. Why Do Kids Need Casts? Kids get casts after breaking a bone, other injuries, and some surgeries. What Are the Different Kinds of Casts? Most casts are made of fiberglass. Fiberglass is a kind of plastic that is moldable and dries hard. Some fiberglass casts are waterproof. Less often, casts are made of plaster of paris. This white powder is mixed with water into a paste. The paste hardens when it's dried. Is There a Waterproof Cast? Yes, there is a cast that can be worn in showers and pools. A waterproof cast is a regular fiberglass cast with a different type of liner. Doctors use waterproof casts only for some kinds of broken bones. How Are Casts Put On? A health care provider such as an orthopedic surgeon, emergency room doctor, physician assistant , orthopedic technician, or nurse practitioner puts on the cast. To put on the cast, the health care provider: wraps a liner of soft material around the injured area (waterproof casts get a different liner) wets the cast material with water wraps the cast material around the first layer waits until the outer layer dries to a hard, protective covering A fiberglass cast gets warm as it hardens. It cools in about 15 minutes. How Can We Prevent Problems With a Cast? If the cast is not waterproof, keep the cast and liner dry. A wet cast or liner can lead to a skin rash or infection. Don't pull out the lining or break off any parts of the cast. If there is a sharp edge, put tape or moleskin on the edge of the cast. If the cast is itchy: Tap on the outside of the cast. Use a hair dryer on the cool or fan-only setting to blow air in at the edges of the cast. Never use an object to scratch under the cast. Scratching can lead to an infection or sores. Don't apply lotion or powder inside the cast. How Should We Care for the Cast? If the Cast Is Waterproof: Flush the cast and liner with clean water to remove soap after showers. Dry the waterproof cast with a hair dryer on the cool setting after showering or swimming. If the Cast Is Not Waterproof: Casts that don't have a special waterproof liner must stay dry. Even kids who are old enough to bathe alone will need help to keep the cast dry while bathing. Younger kids should get sponge baths. To give a sponge bath, use a wet sponge or washcloth to wash and rinse your child. Do not put him or her into the water. Older kids can take baths. Baths are better than showers because it is easier to keep the cast dry in a bath. Before the bath, cover the cast with two plastic bags. First, put one bag on and seal the top with a rubber band. Then, put the second bag on and seal it with another rubber band. Some families use a waterproof plastic cast protector instead of plastic bags. You can buy this at a drugstore. Keep the cast completely out of the water by propping it up on the side of the tub. If the cast or liner gets splashed, gently blow air into it from a hair dryer on the cool or fan-only setting. If some of the cast or liner goes under water or gets very wet, call your doctor. When Should I Call the Doctor? Call your doctor if: The cast feels too tight. The cast was comfortable but becomes uncomfortable. Your child has new pain or pain that gets worse. The fingers or toes get more swollen, change colors, hurt, or feel numb. Something is stuck in the cast, such as a piece of food or small toy. A bad smell or any kind of fluid is coming from the cast. A non-waterproof cast or liner gets wet. How Are Casts Taken Off? Health care providers take off casts with a small electrical saw. The saw cuts through the cast material but stops before it touches the skin. When the cast is off, the skin will probably look pale, dry, or flaky. The hair will look darker and the muscles will look smaller. This is normal and goes away within a few weeks. Looking Ahead Casts can be inconvenient, but most kids don't have any problems with them. Help your child care for the cast so it stays in good condition and does not lead to irritation. Within a few months, most kids can get back to all the activities they enjoy. Back to Articles Related Articles Broken Bones Many kids will have a broken bone at some point. Here's what to expect. Read More How Broken Bones Heal Broken bones have an amazing ability to heal, especially in kids. Full healing can take time, but new bone usually forms a few weeks after an injury. Read More How Long Does it Take for a Broken Bone to Heal? How long does a broken bone take to heal? Find out! Read More Word! Cast If you ever break a bone, you'll probably need a cast to hold the pieces of bone steady while they're healing. Read More Word! Fracture When a bone breaks, it's called a fracture. Read More Growth Plate Fractures Injuries to growth plates, which produce new bone tissue and determine the final length and shape of bones in adulthood, must be treated so that bones heal properly. Read More Getting an X-ray (Video) You'll get an X-ray if your doctor thinks you might have a broken bone. Find out how X-rays are done in this video for kids. Read More X-Ray (Video) This video shows what it's like to get an X-ray. Read More First Aid: Broken Bones A broken bone needs emergency medical care. Here's what to do if you think your child just broke a bone. Read More Stress Fractures It's not always easy to tell if you have a stress fracture, and stress fractures can get worse quickly. This article explains how to prevent and treat them. Read More What to Expect When Your Cast Comes Off You probably can't wait to get back to your normal activities, but it takes a while for a limb that's been in a cast to finish healing. Here's what to expect. Read More Broken Bones What happens when you break a bone? Read More Strains and Sprains Sprains and strains are common injuries, especially for people who play hard or are into sports. Find out what they are and how to recuperate from one. Read More Casts This article for teens has tips on taking care of a cast so it keeps working as it should. Read More Going to a Physical Therapist Physical therapy uses exercises and other special treatments to help people move their bodies. Find out more in this article for kids. Read More Broken Bones Bones are tough stuff - but even tough stuff can break. Find out what happens when a bone fractures. Read More Casts Some injuries will heal best if a cast is used. Find out how they work and how to take care of them in this article for kids. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. 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