Fiberglass Cast Care

Man with leg cast sitting by the bathtub, protecting the cast from getting wet.

It may take up to 2 hours for the fiberglass to get completely hard. Don’t put any weight on the cast during that time or it may break.

To prevent swelling under the cast, do the following for the first 2 days (48 hours):

  • If the cast is on your arm:  Keep it in a sling or raised to shoulder level when you are sitting or standing. Rest it on your chest or on a pillow at your side when lying down. Keep the cast above the level of your heart.

  • If the cast is on your leg:  Keep it propped up above the level of your hip when you are sitting or lying down. Sleep with the cast raised on pillows. Avoid crutch walking as much as possible during this time.

Keep the cast completely dry at all times. Bathe with your cast well out of the water. Protect it with a large plastic bag kept in place with rubber bands or tape. If your cast does get wet, use a hair dryer to warm the cast and speed up the drying process. A wet cast may cause skin problems.

Don’t put creams or objects under the cast if you have itching. If itching persists, contact your provider.

Follow-up care

Follow up with your healthcare provider as advised.

When to get medical advice

Call your healthcare provider right away if any of these occur:

  • The cast cracks

  • Soft or weak spot in the cast

  • The cast and padding get wet and stay wet for more than 24 hours

  • Bad smell from the cast or wound fluid stains the cast

  • Tightness or pressure under the cast gets worse

  • Fingers or toes become swollen, cold, blue, numb, or tingly

  • You can’t move your toes or fingers

  • Pain under the cast gets worse or you feel a burning sensation

  • Skin around the cast becomes red or irritated

  • Fever of 100.4ºF (38ºC) or higher, or as directed by your healthcare provider 

  • Shaking chills

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