Early Signs of Hypothyroidism in Toddlers

Early signs of hypothyroidism in infants and young children can be subtle and easily mistaken for common, benign conditions—making timely recognition critical. Unlike adults, infants with congenital or early-onset hypothyroidism often present with nonspecific symptoms that may include prolonged jaundice lasting beyond two weeks of life, poor feeding or weak suck reflex, excessive sleepiness (hypotonia), constipation, hypotonia, and a low-pitched or hoarse cry. Growth parameters may lag, with decreased weight gain and delayed linear growth. Some infants exhibit hypothermia, cool or mottled skin, and umbilical hernia. In toddlers and preschool-aged children, additional red flags include developmental delays—particularly in speech and motor milestones—as well as fatigue, dry skin, brittle hair, facial puffiness, and slowed heart rate (bradycardia). Untreated, pediatric hypothyroidism can lead to irreversible neurocognitive deficits and growth failure; therefore, newborn screening for thyroid-stimulating hormone (TSH) and thyroxine (T4) is standard in most developed countries and essential for early diagnosis and prompt levothyroxine replacement therapy.