Rickets

How rickets develops

Bones need calcium and phosphate to harden. Vitamin D helps the gut absorb calcium and phosphate. Without enough vitamin D, calcium, or phosphate, the growth plates at the ends of bones cannot mineralize, so they widen and the bones become soft and bend under weight. In adults, whose growth plates have closed, the same process causes osteomalacia.

Causes

Nutritional rickets (most common)

• vitamin D deficiency: from little sun exposure, darker skin, covering clothing, living at high latitudes, or long winters
• exclusive breastfeeding without vitamin D supplements: breast milk is low in vitamin D
• maternal vitamin D deficiency during pregnancy
• low dietary calcium, important in some parts of Africa and Asia
• restrictive diets, including some vegan or dairy-free diets without fortified foods

Other causes

• X-linked hypophosphatemia (XLH): the most common inherited form, where the kidneys lose phosphate. See hypophosphatemia
• vitamin D-dependent rickets: rare genetic defects in vitamin D activation or action
• chronic kidney disease (renal rickets)
• liver disease
• malabsorption: celiac disease, cystic fibrosis, inflammatory bowel disease
• medicines: some anti-seizure drugs

Signs and symptoms

Bone changes

• bowed legs (genu varum) in toddlers, or knock knees (genu valgum) in older children
• thickened wrists and ankles
• rachitic rosary: bead-like swellings where the ribs join the breastbone
• a soft skull (craniotabes) and delayed closing of the soft spot in infants
• a prominent forehead
• chest deformities and curved spine
• fractures with minor trauma

Other signs

• bone pain and tenderness, especially in the legs and spine
• delayed sitting, crawling and walking, or a waddling walk
• muscle weakness and low tone
• poor growth and short stature
• delayed tooth eruption, weak enamel and cavities
• irritability
• in severe vitamin D deficiency: low calcium causing muscle spasms, seizures, and in infants, heart muscle weakness

Diagnosis

• examination of bones, growth and development
• blood tests: calcium, phosphate, alkaline phosphatase (usually high), parathyroid hormone (often high in nutritional rickets) and 25-hydroxyvitamin D (low in nutritional rickets)
• X-rays of the wrists or knees: widened, cupped and frayed growth plates
• kidney function and urine phosphate if an inherited or kidney cause is suspected
• genetic testing for inherited forms

Normal physiological bowing in toddlers is common and improves by about age 2 to 3. Rickets is suspected when bowing is severe, uneven, worsening, or comes with other signs.

Treatment

Nutritional rickets

• vitamin D given by mouth daily for several weeks to months, or as a single large dose in some situations, at a dose prescribed by a doctor
• calcium through diet or supplements
• follow-up blood tests and X-rays to confirm healing, typically within 3 months
• most bone deformities improve with treatment as the child grows. Severe deformities that persist may need bracing or surgery later

Inherited and other forms

• XLH: burosumab, an antibody that reduces phosphate loss, or phosphate supplements with active vitamin D (calcitriol)
• kidney disease: active vitamin D, phosphate control and specialist kidney care
• treating malabsorption, such as a gluten-free diet for celiac disease

Prevention

• vitamin D drops for infants: the American Academy of Pediatrics recommends 400 IU a day for breastfed and partially breastfed babies, starting in the first days of life, and for formula-fed babies drinking less than about a liter (32 oz) of formula a day
• adequate calcium through dairy or fortified alternatives
• safe sun exposure for older children, balanced with skin cancer prevention
• vitamin D supplements for children with darker skin, limited sun exposure, or restrictive diets
• vitamin D during pregnancy as advised by your provider

Outlook

Nutritional rickets heals well with treatment, and most children have no lasting problems if it is caught early. Severe or long-standing cases can leave bowing, short stature or dental problems. Inherited forms need lifelong specialist care but have much better outcomes with modern treatments.

Frequently asked questions

What causes rickets in children?

The most common cause is vitamin D deficiency, from limited sunlight, breastfeeding without vitamin D drops, or darker skin in areas with little sun. Low calcium intake, inherited phosphate-wasting conditions, kidney disease and malabsorption can also cause rickets.

What are the signs of rickets?

Signs include bowed legs or knock knees, thickened wrists and ankles, bead-like bumps on the ribs, delayed walking and teeth, bone pain, muscle weakness and poor growth. Severe cases can cause seizures from low calcium.

Can rickets be cured?

Yes. Nutritional rickets is cured with vitamin D and calcium, and bones usually heal within months. Leg deformities often straighten as the child grows. Inherited forms can be well controlled with specialist treatment.

Does rickets still exist today?

Yes. Rickets has re-emerged in some countries, especially in breastfed babies who do not get vitamin D supplements and in children with darker skin or limited sun exposure. It is easily prevented with vitamin D drops.

How is rickets prevented?

Give breastfed babies vitamin D drops daily, ensure children get enough calcium, allow safe outdoor time, and use vitamin D supplements for children at higher risk. Pregnant women should also maintain adequate vitamin D.