If your child has been given a plaster cast, it is important to care for the cast correctly. The role of a plaster cast is to:

• keep the arm/leg in a certain position, or
• protect the area that has been operated on while it heals.

Positioning

Elevating the limb in plaster will help to reduce swelling, so it is important to keep the limb raised above the level of the heart as much as possible.

• If your child's cast is on their arm and they have been given a sling, always use it to keep the arm up when your child is moving about. Rest the arm on pillows when your child is sitting or lying down.

• If your child's cast is on their leg, use a pillow to prop the leg up while they are resting. Make sure your child uses walking aids (e.g. crutches or wheelchair) if you have been advised to do so, and that they know how to use the crutches safely, including going up and down stairs. See our fact sheet Crutches.

Skin care

Check your child's skin each day for any areas that seem irritated or uncomfortable. It is common for the skin under the cast to get itchy. If there is itchiness, try using a hair-dryer (on a cool setting) at the opening of the cast.

• Don't put anything between the cast and the skin (e.g. do not use a ruler or knitting needle to scratch the skin under the cast). This can irritate the skin and cause an infection.
• Do not use lotions, powders or oils under or around the cast.
  

Cast care

• Keep the plaster cast clean and dry at all times.
• The cast usually dries completely in 48 hours. Allow it to dry naturally and keep it away from direct heat.
• Avoid bumping or hitting the cast.
• Do not paint the cast. This will close the pores of the plaster. Having friends decorate the cast using markers is OK.

Swelling

It is common to get some swelling of the fingers or toes around a plaster cast.

• Carefully check the cast to make sure it is not too tight. There should be a gap between the cast and your child's skin.
• Encourage your child to wiggle and move their fingers or toes often to help keep the blood flowing.

It is important to monitor your child for poor blood supply or swelling in their fingers or toes. If this happens:

• The skin may look pale or bluish in colour.
• The fingers or toes are cool or hot to touch.
• Your child may say they have pins and needles or numbness.
• Your child may not be able to move their fingers or toes.

If these symptoms happen, raise the arm or leg above the level of the heart and take your child to your nearest hospital emergency department. 

When to see a doctor

Take your child to the GP or local emergency department if:

• they have severe pain.
• the cast has become damaged in any way.
• you notice any problems such as areas that are becoming red/swollen/hot, damaged skin or a bad smell coming from the cast.
• the cast has become loose or slipped from its original position.
  

Follow-up

When you go home from hospital, you will be advised how long your child needs the cast on, and when and where to go to have it reviewed or removed.

Key points to remember

• Keep the limb in plaster raised above heart level as much as possible.
  
• Keep the cast clean and dry at all times.
  
• It is common for the skin under the cast to get itchy, but do not put anything under the cast to scratch the skin. Try blowing cool air from a hair dryer instead.
• Encourage your child to move their fingers/toes often to keep the blood flowing.

For more information

• Contact your GP or treating hospital
• Kids Health Info fact sheet: Fractures (broken bones)
• Kids Health Info fact sheet: Crutches
• Be Positive: A child's guide to hospital:  Fracture Clinic
  

Developed by The Royal Children's Hospital Surgery division. We acknowledge the input of RCH consumers and carers.

Reviewed December 2023.

Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.