Rickets causes a child's bones to become soft and weak, which can lead to bone deformities.

The signs and symptoms of rickets can include:

• pain – the bones affected by rickets can be sore and painful, so the child may be reluctant to walk or may tire easily; the child's walk may look different (waddling)
• skeletal deformities – thickening of the ankles, wrists and knees, bowed legs, soft skull bones and, rarely, bending of the spine
• dental problems – including weak tooth enamel, delay in teeth coming through and increased risk of cavities
• poor growth and development – if the skeleton doesn't grow and develop properly, the child will be shorter than average
• fragile bones – in severe cases, the bones become weaker and more prone to fractures

Some children with rickets may also have low levels of calcium in their blood (hypocalcaemia). This can make the symptoms of rickets worse and can also cause muscle cramps, twitching, tingling in the hands and feet, and fits.

Adults can experience similar symptoms such as bone pain, muscle weakness and fragile bones that are more prone to fractures. In adults, these symptoms are known as osteomalacia.

Visit Arthritis Research UK to find out more about symptoms of osteomalacia.

When to seek medical advice

If your child has any signs or symptoms of rickets, such as bone pain, delayed growth, muscle weakness or skeletal problems, take them to your GP for a check-up.

If you are an adult and you're experiencing bone pain or muscle weakness see your GP to get it checked out.

Rickets usually occurs because of a lack of vitamin D or calcium, although it can also be caused by a genetic defect or another health condition.

Lack of vitamin D and calcium

The most common cause of rickets is a lack of vitamin D or calcium in a child's diet. Both are essential for children to develop strong and healthy bones.

Sources of vitamin D are:

• sunlight – your skin produces vitamin D when it's exposed to the sun, and we get most of our vitamin D this way
• food – vitamin D is also found in some foods, such as oily fish, eggs and fortified breakfast cereals
• dietary supplements

Calcium is commonly found in dairy products, such as milk, cheese and yoghurt, and green vegetables, such as broccoli and cabbage.

Over time, a vitamin D or calcium deficiency will cause rickets in children and soft bones (osteomalacia) in adults.

See preventing rickets for more information and advice about ensuring your child gets enough vitamin D and calcium.

Who's at risk?

Any child who doesn't get enough vitamin D or calcium can develop rickets, but there are certain groups of children who are more at risk.

For example, rickets is more common in children of Asian, African-Caribbean and Middle Eastern origin because their skin is darker and needs more sunlight to get enough vitamin D.

Babies born prematurely are also at risk of developing rickets because they build up stores of vitamin D while they're in the womb. Babies who are exclusively breastfed, especially for longer than 6 months, may also be at risk of vitamin D deficiency.

It is recommended that:

• pregnant and breastfeeding women should consider taking a daily supplement containing 10 micrograms (mcg) of vitamin D from at least October to March
• babies from birth to 1 year of age, whether exclusively or partially breastfed, should be given a daily supplement containing 8.5 to 10mcg of vitamin D, to make sure they get enough
• babies fed infant formula do not need a vitamin D supplement until they are receiving less than 500ml (about a pint) of infant formula a day, because infant formula is fortified with vitamin D
• children aged 1 to 4 years old should be given a daily supplement containing 10mcg of vitamin D

For more information, read who should take vitamin D supplements.

Genetic defect

Rare forms of rickets can also occur in some inherited (genetic) disorders. For example, hypophosphatemic rickets is a genetic disorder where the kidneys and bones deal abnormally with phosphate.

Phosphate binds to calcium and is what makes bones and teeth hard. This leaves too little phosphate in the blood and bones, leading to weak and soft bones.

Other types of genetic rickets affect certain proteins in the body that are used by vitamin D.

Underlying conditions

Occasionally, rickets develops in children with rare forms of kidney, liver and intestinal conditions. These can affect the absorption of vitamins and minerals.

As most cases of rickets are caused by a vitamin D and calcium deficiency, it's usually treated by increasing a child's intake of vitamin D and calcium.

Vitamin D and calcium levels can be increased by:

• eating more foods that are rich in calcium and vitamin D
• taking daily calcium and vitamin D supplements
• having a vitamin D injection each year – this is only necessary if the child can't take the supplements by mouth or has intestinal or liver disease

Sunlight also helps our bodies to make vitamin D, so you may be advised to increase the amount of time your child spends outside.

Your GP will advise you about how much vitamin D and calcium your child will need to take. This will depend on their age and the cause of rickets. If your child has problems absorbing vitamins, they may need a higher dose.

See preventing rickets for more information about dietary sources of vitamin D and calcium, as well as advice about getting vitamin D from sunlight.

Treating complications and related conditions

When rickets occurs as a complication of another medical condition, treating the underlying condition will often cure the rickets.

If your child has a bone deformity caused by rickets, such as bowed legs or curvature of the spine, your GP may suggest treatment to correct it. This may include surgery.

Genetic rickets

A combination of phosphate supplements and a special form of vitamin D is required for the treatment of hypophosphatemic rickets, where a genetic defect causes abnormalities in the way the kidneys and bones deal with phosphate.

Children with other types of genetic rickets need very large amounts of a special type of vitamin D treatment.

Supplement side effects

It's very unusual to get side effects from vitamin D, calcium or phosphate supplements if they're given in the correct dose. Your doctor will advise you about how much supplement is needed, for how long, and the monitoring of treatment.

If the vitamin D or calcium dose is too high or the treatment is continued for too long or isn't carefully monitored, it can raise calcium levels in the blood. This can result in a condition called hypercalcaemia.

Symptoms of hypercalcaemia include:

• passing a lot of urine
• feeling thirsty
• reduced appetite
• nausea, abdominal pain, constipation and vomiting
• dizziness and headaches
• bone pain

See your GP immediately if you or your child have any of these symptoms.

Osteomalacia

If you have osteomalacia – the adult form of rickets that causes soft bones – treatment with supplements will usually cure the condition.

However, it may be several months before any bone pain and muscle weakness is relieved.

You should continue taking vitamin D supplements regularly to prevent the condition returning.

There are several steps you can take to help prevent rickets.

These include ensuring your child:

• has a healthy, balanced diet (read about good dietary sources of vitamin D
• spends some time outside in the sun
• takes a vitamin D supplement

Babies from birth to 1 year, including those who are exclusively or partially breastfed, need 8.5 to 10 micrograms (mcg) of vitamin D a day.

Children from the age of 1 year and adults need 10mcg of vitamin D a day.

Supplements

It is recommended that:

• pregnant and breastfeeding women should consider taking a daily supplement containing 10mcg of vitamin D from at least October to March
• babies from birth to 1 year of age, whether exclusively or partially breastfed, should be given a daily supplement containing 8.5 to 10mcg of vitamin D, to make sure they get enough
• babies fed infant formula do not need a vitamin D supplement until they are receiving less than 500ml (about a pint) of infant formula a day, because infant formula is fortified with vitamin D
• children aged 1 to 4 years old should be given a daily supplement containing 10mcg of vitamin D

For more information, read about who should take vitamin D supplements.

Sunlight

Sunlight is a good source of vitamin D and it's where we get most of our vitamin D from. The vitamin forms under the skin after sun exposure.

In the UK, a short period of exposure on the hands and face when the sun is at its strongest (between 11am and 3pm) from late March/April to the end of September is enough for most people.

You won't get vitamin D from the sun if you wear sunscreen, but you should apply sunscreen with a sun protection factor (SPF) of at least 15 before your skin starts to turn red or burn. This will help protect your skin from sun damage.

While it's important for children to spend time in the sun to prevent rickets, babies and young children have very sensitive skin that burns easily. They need to use stronger sunscreen and be covered up when out in the sun.

In the UK, your skin isn't able to make vitamin D from the sun from October to early March because the sunlight isn't strong enough. However, you can get vitamin D from your body's stores and from food sources during this period.

Read more about vitamin D and sunlight and staying safe in the sun.

Healthy Start

Some families are eligible for free vitamin supplements from the government's Healthy Start scheme.

Find out if you qualify for Healthy Start. You can also call the Healthy Start helpline on 0345 607 6823 or email their helpdesk from the contact form on the Healthy Start website.