Rickets is a childhood bone disorder where bones become soft, weak, and prone to bending or fracturing. It happens when a growing child’s body can’t deposit enough minerals into developing bones, most often because of a severe shortage of vitamin D. While rickets was once considered a disease of the past, it still affects children worldwide, including in developed countries where indoor lifestyles and limited sun exposure have become the norm.
What Causes Rickets
Bones need calcium and phosphorus to harden properly. Vitamin D is the key that unlocks the body’s ability to absorb calcium from food. Without enough vitamin D, a child can drink plenty of milk and still not get calcium into their bones. This is the most common pathway to rickets by far.
Children can become vitamin D deficient in several ways. Limited sunlight exposure is the biggest factor, since the skin produces vitamin D when exposed to ultraviolet B rays. Children with darker skin need more sun exposure to produce the same amount, which partly explains why rickets rates are higher in dark-skinned children living at northern latitudes. Exclusively breastfed infants are also at elevated risk because breast milk contains very little vitamin D on its own.
Less commonly, rickets develops even when vitamin D levels are adequate. Some children have genetic conditions that prevent the kidneys from retaining phosphorus, leading to a form called hypophosphatemic rickets. Others have rare inherited disorders that block the body from activating vitamin D properly. Certain kidney and liver diseases can also interfere with vitamin D metabolism, and prolonged use of some anti-seizure medications can increase the breakdown of vitamin D in the body.
Signs and Symptoms
Rickets typically appears between 6 months and 3 years of age, the period when bones are growing most rapidly. The earliest signs are often subtle. A child may be irritable, sweat excessively around the head, and show delays in sitting, crawling, or walking. The soft spot on an infant’s skull may take longer than normal to close.
As the condition progresses, the skeletal changes become visible. The classic sign is bowing of the legs, where the knees curve outward when the child stands. Other physical changes include:
- Thickened wrists and ankles from swelling at the growth plates
- A bumpy ribcage where bead-like knobs form along the ribs (sometimes called a “rachitic rosary”)
- A protruding breastbone that pushes the chest forward
- A widened, flattened skull in severe cases
- Delayed tooth eruption and soft, cavity-prone enamel
Children with rickets often experience bone pain, particularly in the legs, pelvis, and spine. Their muscles may feel weak, and they tire easily during physical activity. In severe cases, low calcium levels can trigger muscle cramps or even seizures, which sometimes become the first sign that prompts a diagnosis.
How Rickets Is Diagnosed
A doctor can often suspect rickets from a physical exam alone, especially when a child has visibly bowed legs or swollen joints at the wrists. Blood tests confirm the picture by showing low levels of calcium, phosphorus, or vitamin D, along with elevated levels of a bone enzyme called alkaline phosphatase, which spikes when bone is turning over abnormally fast.
X-rays of the wrists or knees are the most reliable way to confirm the diagnosis. In a child with rickets, the growth plates at the ends of bones appear widened, frayed, and cupped rather than crisp and well-defined. These images also help gauge severity and track whether treatment is working over time.
Treatment and Recovery
For the most common form caused by vitamin D deficiency, treatment is straightforward: replacing what’s missing. Children receive vitamin D supplements, often at high doses initially, along with calcium if levels are low. Most children start showing improvement in blood work within a few weeks, and X-rays typically look noticeably better within three to six months.
Skeletal deformities like bowed legs often correct themselves as the bones remineralize and the child continues to grow, especially when treatment starts early. Mild to moderate bowing in a toddler may fully straighten out by school age without any intervention beyond supplements. Severe deformities that persist after the underlying deficiency is corrected sometimes require bracing or, rarely, surgical correction later in childhood.
The genetic and kidney-related forms of rickets require more specialized treatment. Hypophosphatemic rickets, for instance, is managed with phosphorus supplements and a specialized form of vitamin D, often throughout the child’s growing years. A newer targeted therapy has improved outcomes significantly for the most common inherited type.
Long-Term Outlook
When caught early and treated properly, nutritional rickets is largely reversible. Bones reharden, growth resumes at a normal pace, and many children have no lasting effects. The exceptions tend to be cases diagnosed late, where significant skeletal deformity or growth stunting has already occurred. Some children who had severe rickets retain a degree of leg bowing or short stature into adulthood, though this is uncommon with modern treatment.
Dental problems caused by rickets, including enamel defects and a higher cavity risk, don’t reverse with vitamin D supplementation because the damage to developing teeth is already done. These children may need more intensive dental care as they grow.
Prevention
Most cases of rickets are preventable. The American Academy of Pediatrics recommends that all breastfed and partially breastfed infants receive 400 IU of vitamin D daily starting in the first few days of life. Formula-fed infants generally get enough through fortified formula, but only if they’re drinking at least about 32 ounces per day.
For older children, regular sun exposure helps, but the amount needed varies enormously based on skin tone, latitude, season, and sunscreen use. Dietary sources of vitamin D include fortified milk, fatty fish like salmon and mackerel, egg yolks, and fortified cereals. In practice, many children don’t get enough from food alone, which is why supplementation remains the most reliable safeguard, particularly for children with darker skin, those living in northern climates, or those who spend most of their time indoors.