Thyroid in Children
The thyroid is a small, butterfly-shaped gland at the front of the neck, and it has an outsized effect on nearly every system in a child’s body. It regulates metabolism, growth, brain development, energy levels, heart rate, and even puberty. When it’s not working properly, the effects show up across the board, and because the symptoms are often gradual and nonspecific, thyroid problems in children frequently go unrecognized for longer than they should. At Pediatricz Now, thyroid screening is part of how we take a complete look at your child’s health.
The Two Main Thyroid Disorders in Children
Thyroid disorders fall into two categories depending on whether the gland is underactive or overactive, and the experience for the child is quite different in each case.
Hypothyroidism is when the thyroid doesn’t produce enough hormone. It’s the most common thyroid disorder in children. The body slows down in response: metabolism drops, growth stalls, energy is low, and development can lag. Hypothyroidism can be congenital, meaning a baby is born with an underactive thyroid, often because the gland didn’t form properly during pregnancy. All newborns in the U.S. are screened for congenital hypothyroidism at birth because untreated cases can lead to serious developmental and intellectual impairment. The acquired form develops later in childhood or adolescence, most commonly caused by Hashimoto’s thyroiditis, an autoimmune condition in which the body’s immune system attacks the thyroid gland. Hashimoto’s is significantly more common in girls, affecting approximately 1 in 300.
Hyperthyroidism is the opposite: the thyroid produces too much hormone and the body speeds up. Heart rate increases, children may feel anxious or irritable, lose weight despite eating normally, and have difficulty sleeping. The most common cause in children is Graves’ disease, another autoimmune condition, this one causing the body to produce antibodies that overstimulate the thyroid.
Children with other autoimmune conditions, including Type 1 diabetes, are at higher risk for thyroid disorders and benefit from more proactive monitoring.
Symptoms That Are Easy to Miss
Thyroid symptoms in children are easy to attribute to other causes, which is part of why they often go undetected. The symptoms develop gradually, and children don’t always have the language to describe what they’re feeling.
With hypothyroidism, the signs tend to be quiet ones: persistent fatigue, unexplained weight gain, constipation, dry skin, feeling cold when others don’t, slowed growth, delayed puberty, and poor school performance. A hoarse voice and an enlarged thyroid gland at the front of the neck, called a goiter, can also be present. In younger children, slow growth and delayed tooth development are flags. In teens, delayed or irregular puberty is another.
Hyperthyroidism presents differently. Children may seem unusually anxious, have difficulty sitting still, experience heart palpitations, sweat more than normal, lose weight without trying, and have frequent bowel movements. Academic performance can drop here too, but for different reasons: difficulty concentrating and sleep disruption rather than low energy.
One nuance worth knowing: sometimes a child will test positive for thyroid antibodies but have normal thyroid hormone levels. That doesn’t mean treatment is needed, but it does mean monitoring is. Positive antibodies indicate elevated risk and warrant follow-up testing over time.
How Thyroid Disorders Are Diagnosed and Managed
Diagnosis begins with a blood test measuring TSH (thyroid-stimulating hormone) and thyroid hormone levels (T4). TSH is produced by the pituitary gland and acts as a signal to the thyroid. When TSH is high, it means the pituitary is working harder to stimulate an underperforming thyroid. When TSH is low, it suggests the thyroid is overproducing and the pituitary has pulled back. These two markers together give a clear picture of whether the thyroid is in balance.
If the blood work points to a thyroid disorder, additional testing may follow. Thyroid antibody testing helps confirm whether an autoimmune process like Hashimoto’s or Graves’ is involved. A thyroid ultrasound may be ordered to look at the structure of the gland, identify nodules, or assess for irregularities. Thyroid nodules are less common in children than in adults, but when they do occur, they warrant careful evaluation.
For hypothyroidism, treatment is a daily oral thyroid hormone replacement medication called levothyroxine. It’s well-tolerated with no significant side effects when dosed correctly. Dosing is adjusted as the child grows, and regular blood work is needed to keep levels in the right range. Some children with mild or transient hypothyroidism may eventually be weaned off treatment, but most will need it long term.
For hyperthyroidism, treatment options include anti-thyroid medications that reduce hormone production, radioactive iodine therapy, or in some cases surgery. The right approach depends on the child’s age, the severity of the condition, and how they respond to initial treatment.
When Professional Guidance May Be Helpful
If your child has been persistently tired, gained weight without a clear reason, seems unusually anxious, has slowed growth, or is showing signs of delayed puberty, thyroid function is worth checking. The same applies if there’s a family history of thyroid disease or autoimmune conditions, or if your child has been diagnosed with Type 1 diabetes or Down syndrome, both of which carry elevated thyroid risk.
A simple blood test is all it takes to get started. From there, we can determine whether further evaluation is needed and put a management plan in place.
Frequently Asked Questions
Can a child's thyroid disorder affect their height?
Yes, and this is one of the more significant effects of untreated hypothyroidism in growing children. Thyroid hormone plays a direct role in stimulating growth hormone and bone development. Children with prolonged untreated hypothyroidism can experience stunted growth and delayed bone age. When treatment is started early and maintained consistently, most children are able to recover their normal growth trajectory.
Is Hashimoto's thyroiditis hereditary?
There is a strong genetic component. Children with a parent or sibling who has Hashimoto’s or another autoimmune thyroid condition are at meaningfully higher risk. If autoimmune thyroid disease runs in your family, mentioning that history at your child’s next well visit is worthwhile, even if your child has no symptoms yet.
Can stress or illness temporarily affect thyroid test results?
Yes. Certain acute illnesses can cause temporary changes in thyroid hormone levels that normalize once the child recovers, a pattern sometimes called euthyroid sick syndrome. This is one reason we interpret thyroid results in the context of a child’s overall clinical picture rather than acting on a single out-of-range value in isolation.
At what age do thyroid problems most commonly develop in children?
Congenital hypothyroidism is present from birth and caught through newborn screening. Acquired hypothyroidism and Graves’ disease most commonly emerge during adolescence, with the peak incidence in the teenage years. Girls are diagnosed significantly more often than boys across both conditions.
Can a child with a treated thyroid disorder participate in sports and normal activities?
In most cases, yes. Children whose thyroid levels are well-controlled with medication typically have no restrictions on physical activity. Uncontrolled hyperthyroidism is the exception, as the elevated heart rate and cardiovascular strain it causes can make intense physical exertion risky until hormone levels are stabilized.