Your Child's Fiberglass Cast: Care Instructions

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A cast protects a broken bone or other injury so it has time to heal. Most casts are made of fiberglass. When your child wears a cast, you can't remove it yourself. A doctor or a technician will take it off.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor if your child is having problems. It's also a good idea to know your child's test results and keep a list of the medicines your child takes.

How can you care for your child at home?

General care

  • Follow the doctor's instructions for when your child can start using the limb that has the cast. Fiberglass casts dry quickly and are soon hard enough to protect the injured arm or leg.
  • When it's okay to put weight on a leg or foot cast, don't let your child stand or walk on it unless it's designed for walking.
  • Prop up the injured arm or leg on a pillow anytime your child sits or lies down during the first 3 days. Try to keep it above the level of your child's heart. This will help reduce swelling.
  • Put ice or a cold pack on your child's cast for 10 to 20 minutes at a time. Try to do this every 1 to 2 hours for the next 3 days (when your child is awake). Put a thin cloth between the ice and your child's cast. Keep the cast dry.
  • Ask your doctor if you can give your child acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) for pain. Be safe with medicines. Read and follow all instructions on the label.
    • Do not give your child two or more pain medicines at the same time unless the doctor told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen (Tylenol) can be harmful.
  • Help your child do exercises as instructed by the doctor or physical therapist. These exercises will help keep your child's muscles strong and joints flexible while the cast is on.
  • Remind your child to wiggle their fingers or toes on the injured arm or leg often. This helps reduce swelling and stiffness.

Water and your child's cast

  • Try to keep your child's cast as dry as you can. The fiberglass part of the cast can get wet. But getting the inside wet can cause problems.
  • Use a bag or tape a sheet of plastic to cover your child's cast when your child takes a shower or bath or has any other contact with water. (Don't let your child take a bath unless your child can keep the cast out of the water.) Moisture can collect under the cast and cause skin irritation and itching. It can make infection more likely if your child had surgery or has a wound under the cast.
  • If your child has a water-resistant cast, ask the doctor how often it can get wet and how to take care of it.

Skin care

  • Try blowing cool air from a hair dryer or fan into the cast to help relieve itching. Never stick items under your child's cast to scratch the skin.
  • Don't use oils or lotions near your child's cast. If the skin gets red or irritated around the edge of the cast, you may pad the edges with a soft material or use tape to cover them.

When should you call for help?

Call your child's doctor now or seek immediate medical care if:

  • Your child has increased or severe pain.
  • Your child feels a warm or painful spot under the cast.
  • Your child has problems with the cast. For example:
    • The skin under the cast burns or stings.
    • The cast feels too tight or too loose.
    • There is a lot of swelling near the cast. (Some swelling is normal.)
    • Your child has a new fever.
    • There is drainage or a bad smell coming from the cast.
  • Your child's foot or hand is cool or pale or changes color.
  • Your child has trouble moving their fingers or toes.
  • Your child has symptoms of a blood clot in the arm or leg (called a deep vein thrombosis). These may include:
    • Pain in the arm, calf, back of the knee, thigh, or groin.
    • Redness and swelling in the arm, leg, or groin.

Watch closely for changes in your child's health, and be sure to contact your doctor if:

  • The cast is breaking apart.
  • Your child does not get better as expected.

Where can you learn more?

Go to

Enter O867 in the search box to learn more about "Your Child's Fiberglass Cast: Care Instructions".

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.