Introduction

Hypothyroidism in children is a condition that often goes unnoticed, but if left untreated, it can have a major impact on a child’s development, learning, and overall health.

When 6-year-old Aisha’s parents brought her to my clinic, they were concerned that she was always tired, smaller than her peers, and struggling to get to school. After a few simple tests, we diagnosed her with pediatric hypothyroidism a condition where the thyroid gland doesn’t produce enough thyroid hormone. With proper treatment, Aisha is now thriving, but her story is a reminder of why awareness is important.

As a physician and medical educator, I have seen how hypothyroidism in children can go unnoticed for years if parents don’t recognize the early signs.

In this blog, we’ll cover everything parents need to know about hypothyroidism in children including its causes, symptoms, diagnosis, treatment, complications, and long-term outlook. You’ll also find practical tips on nutrition, lifestyle, and how to support your child emotionally and medically.

What is hypothyroidism in children?

Hypothyroidism in children is a condition in which the thyroid gland doesn’t produce enough thyroid hormone, which is essential for growth, brain development, and metabolism. It can be present at birth (congenital hypothyroidism) or develop later in childhood (acquired hypothyroidism).

Symptoms vary with age. In infants, it can cause prolonged jaundice, poor feeding, and delayed growth. In older children, it can cause fatigue, poor growth, constipation, dry skin, and difficulty concentrating. The condition is usually diagnosed through blood tests that measure TSH (thyroid-stimulating hormone) and free T4 levels. The most common treatment is daily thyroid hormone replacement with levothyroxine, which helps restore normal growth and development. With early diagnosis and proper management, children with hypothyroidism can live completely normal and healthy lives.

Understanding Hypothyroidism in Children

A butterfly-shaped organ located at the base of the neck, the thyroid gland produces hormones (T3 and T4) that regulate metabolism, growth, and brain development. In children, these hormones are especially important because they affect:

• Height and weight gain
• Bone and muscle development
• Cognitive performance
• Adolescence and hormonal balance

Hypothyroidism in children occurs when the gland fails to produce enough hormones. The condition can be either congenital (present at birth) or acquired (develops later in life).

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Causes of Hypothyroidism in Children

Understanding the causes of hypothyroidism in children helps parents know what to expect.

Congenital Hypothyroidism

Affected in about 1 in 2,000 to 4,000 newborns (CDC).

Causes include thyroid dysgenesis (a missing, small, or misplaced thyroid gland) or birth defects in thyroid hormone production.

Without early screening, it can lead to intellectual disability.

Acquired Hypothyroidism

More common in older children and adolescents.

Causes include:

• Autoimmune thyroiditis (Hashimoto’s disease) – the most common cause worldwide.
• Iodine deficiency or excess (still common in some areas, WHO).
• Radiation or surgery involving the neck.
• Medications such as lithium or amiodarone.

Symptoms of hypothyroidism in children

It is important to recognize the symptoms of hypothyroidism in children early, as many symptoms can be mistaken for normal changes in growth or behavior. Below is a detailed list:

Early and common symptoms

• Persistent fatigue and low energy
• Increased sleepiness or lethargy
• Cold intolerance (feeling cold when others are comfortable)
• Constipation that does not improve with dietary changes
• Hoarse voice or slurred speech

Physical symptoms

• Dry, coarse, or brittle hair
• Fluffy, dry, or scaly skin
• Puffy face and swollen eyelids.
• In some cases, an enlarged thyroid gland (goiter)
• Slow heart rate (bradycardia)
• Swelling of the hands and feet (myxedema)

Growth and developmental symptoms

• Short stature or slow growth compared to peers
• Delayed eruption of teeth
• Delayed puberty or irregular menstrual periods in adolescents
• Weight gain despite poor appetite
• Weak muscle tone and clumsiness

Cognitive and behavioral symptoms

• Difficulty concentrating in school
• Poor memory and decreased ability to learn
• Mood swings (irritability, sadness, or depression)
• Slow reflexes and delayed responses

Severe or advanced symptoms (if left untreated for a long time)

• Very slow growth and delayed bone age (skeletal development)
• Fat facial features (broad nose, thick lips)
• Intellectual disability (if congenital hypothyroidism is not treated in childhood (See)
• Slow speech and delayed motor skills.

Doctor’s Note: In my clinical practice, I have seen that the most common symptoms that parents notice early on are fatigue, constipation, and slow growth. However, because these symptoms are subtle, children can go years without being diagnosed unless a parent or doctor specifically looks for hypothyroidism.

Diagnosis of Hypothyroidism in Children

Early and accurate diagnosis is essential.

Screening in infants

Most countries screen newborns with TSH testing, which detects congenital hypothyroidism within days of birth.

WHO recommends universal newborn screening programs.

Diagnostic tests in older children

• TSH and free T4 levels gold standard.
• Thyroid antibodies (TPO-Ab, Tg-Ab) for autoimmune causes.
• Ultrasound of the thyroid gland if structural abnormality is suspected.

Treatment of Hypothyroidism in Children

Treatment of hypothyroidism in children is straightforward but life changing.

Levothyroxine replacement

• Synthetic thyroid hormone is taken orally once daily.
• Dosage is adjusted according to age and weight.
• Safe and effective if taken regularly.

Monitoring progress

• TSH and free T4 are checked every 6-12 weeks initially, then every 3-6 months.
• Growth charts are monitored to ensure normal growth.

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Lifestyle and nutritional support

• Adequate iodine intake through diet (iodized salt, seafood).
• Balanced diet with iodine rich foods.
• Encourage exercise for healthy growth.

Complications of untreated hypothyroidism in children

Developmental delay and intellectual disability (especially in congenital cases).

• Stunted growth and short stature.
• Delayed puberty.
• Emotional and behavioral problems such as depression.

Hypothyroidism in Newborns: Early Symptoms, Diagnosis, and Treatment

Hypothyroidism in newborns is one of the most important conditions to recognize early, as thyroid hormones play a crucial role in brain development in the first years of life. If left untreated, it can lead to serious complications such as developmental delays, poor growth, and even intellectual disability. Fortunately, with timely diagnosis and treatment, babies with hypothyroidism can live completely normal, healthy lives.

Early Symptoms of Hypothyroidism in Newborns

Many newborns with hypothyroidism appear normal at birth, which is why the condition often goes unnoticed without screening. Subtle signs may include:

• Prolonged jaundice (yellowing of the skin and eyes)
• Poor diet and excessive sleep
• Constipation from the first few days of life
• A swollen face and swollen eyelids.
• Large tongue (macroglossia)
• Harsh cry
• Umbilical hernia

Diagnosis of hypothyroidism in newborns

Most countries now conduct newborn screening tests within the first few days after birth. A simple heel prick blood test checks levels of thyroid-stimulating hormone (TSH) and free thyroxine (T4). If the results are abnormal, follow up with confirmatory testing. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), universal newborn screening is the gold standard for preventing lifelong complications.

Treatment of Hypothyroidism in Newborns

• Levothyroxine therapy (synthetic thyroid hormone) is the treatment of choice.
• It is given as a daily oral dose, usually crushed and mixed with a small amount of breast milk or formula.
• The dosage is carefully adjusted based on the baby’s weight, age, and regular blood test results.
• With early treatment ideally started within the first two weeks of life infants usually achieve normal growth and brain development.

Doctor’s advice: In my practice, I always remind parents that consistency is key. Even missing a few doses in the early months can affect a baby’s long-term development. Setting reminders and making medication part of the daily feeding routine helps ensure consistency.

Hypothyroidism in Children Associated with Other Diseases

Children with hypothyroidism may also develop or be at increased risk for other health conditions. It is important to recognize these associations for timely diagnosis and management:

Type 1 Diabetes Mellitus – Autoimmune hypothyroidism (Hashimoto’s thyroiditis) often occurs with type 1 diabetes.

Celiac Disease – Children with celiac disease are at increased risk for thyroid disorders due to the shared autoimmune mechanism.

Down Syndrome – Hypothyroidism is more common in children with Down syndrome, which requires regular thyroid screening.

Turner Syndrome – Girls with Turner syndrome are more likely to have hypothyroidism.

Other autoimmune disorders – Conditions such as vitiligo, alopecia areata, and Addison’s disease can occur with autoimmune thyroid disease.

Doctor’s advice: In my practice, I always recommend that children with hypothyroidism (especially autoimmune) be screened for other autoimmune conditions if symptoms suggest them.

Prevention and Diagnosis

Congenital hypothyroidism cannot be prevented, but early screening prevents complications.

Iodine deficiency related hypothyroidism can be prevented with iodized salt (WHO campaigns have significantly reduced rates).

Early treatment is the best prognosis, most children live normal, healthy lives.

Living with Hypothyroidism, A Parent’s Guide

• Take medication consistently at the same time each day.
• Attend regular follow ups.
• Support your child emotionally and academically.
• Teach older children about their condition to encourage responsibility.

Conclusion

Hypothyroidism in children can be overwhelming for parents, but the reality is reassuring when detected early and treated appropriately, children can grow, learn, and develop like their peers. From understanding the causes of hypothyroidism in children, to recognizing the early signs of hypothyroidism in children, and following the right treatment for hypothyroidism in children, awareness really makes a difference.

As a doctor, I remind parents that managing hypothyroidism isn’t just about taking medication it’s about regular follow-ups, balanced nutrition, emotional support, and staying informed. Whether your child was diagnosed as an infant or developed hypothyroidism later in life, proper medical care ensures an excellent long-term outlook.

If you notice persistent fatigue, slow growth, or developmental delays, don’t ignore these warning signs talk to your pediatrician and request a thyroid test. Early action today means a healthier tomorrow for your child.

Call to Action

If you suspect your child may have symptoms of hypothyroidism, don’t delay early testing and treatment make all the difference. As a doctor, I encourage you to leave your questions or experiences in the comments or reach out for a consultation. Together, we can ensure that every child with hypothyroidism grows up healthy and thriving.

References:

CDC – Congenital Hypothyroidism Facts

Mayo Clinic – Hypothyroidism in Children

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🧑‍⚕️ About the Author

 Dr. Asif, MBBS, MHPE

Dr. Asif is a medical doctor and medical educationist with expertise in simplifying complex health topics for the general public. With a passion for preventive health and evidence-based writing, he helps readers make informed choices about their well-being.

✅ Medically Reviewed By

Dr. T.G., MBBS, FCPS (Endocrinology)

Associate Professor, Endocrinology Ward, HMC Hospital

With over 20 years of clinical experience in managing endocrine disorders, Dr. T.G. ensures that the content is accurate, reliable, and clinically relevant.

⚠️ Medical Disclaimer

This blog is intended for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard or delay medical advice based on content you read here.