Diffuse Scalp Hair Loss Due to Levothyroxine Overdose

In 2015, a case study was conducted on a 10-month-old infant diagnosed with hypothyroidism who experienced diffuse scalp hair loss due to an overdose of levothyroxine. The infant was initially given a dose of 100 μg/day of levothyroxine, which led to a sudden onset of hair loss involving 90% of the scalp area. The high serum T4 level (18.2 μg/dL) suggested hyperthyroidism, leading to the conclusion that the hair loss was due to thyroxine overdose. The levothyroxine dose was then reduced by 50% to 50 μg/day, and a follow-up after 15 days showed significant hair regrowth. Six weeks later, the T4 level was still slightly high, so the dose was further decreased to 37.5 μg/day. Subsequent follow-ups showed normal scalp hair growth without further hair loss. The study concluded that hair follicles need adequate and correct levels of thyroxine for appropriate hair growth, and children on levothyroxine should be monitored for serum levels of T3 and T4.