Does levothyroxine cause hair loss
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Does Levothyroxine Cause Hair Loss?
Introduction to Levothyroxine and Hair Loss
Levothyroxine is a synthetic thyroid hormone commonly prescribed to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. While it is effective in managing thyroid hormone levels, there have been reports and studies indicating that levothyroxine can cause hair loss, particularly when dosages are not properly managed.
Hair Loss Due to Levothyroxine Overdose
Case Study: Diffuse Scalp Hair Loss in an Infant
A notable case involved a 10-month-old infant diagnosed with hypothyroidism who was started on a high dose of levothyroxine (100 µg/day). Within ten days, the infant experienced sudden, diffuse scalp hair loss, characterized by thin and easily pluckable hair. This condition, known as anagen effluvium, was attributed to a levothyroxine overdose, as the infant's serum T4 levels were significantly elevated, indicating hyperthyroidism. Upon reducing the levothyroxine dose, there was a dramatic regrowth of hair, suggesting that the hair loss was reversible with proper dosage adjustment1.
Mechanism of Hair Loss
Hair growth cycles through three phases: anagen (growth), catagen (transitional), and telogen (resting). Most hair follicles are in the anagen phase at any given time. Medications, including levothyroxine, can disrupt this cycle, leading to two types of hair loss: telogen effluvium and anagen effluvium. Anagen effluvium, which occurs within days to weeks of starting a medication, was observed in the infant case due to the high dosage of levothyroxine1.
Hair Loss in Hypothyroidism and Hyperthyroidism
Both hypo- and hyperthyroidism are associated with hair loss. In hypothyroidism, hair tends to become dry, coarse, brittle, and slow-growing, with an increased proportion of hair in the telogen phase. Conversely, hyperthyroidism can lead to fine, soft, and greasy hair with reduced tensile strength and thinned hair shafts, despite increased hair matrix proliferation1.
Conclusion
Levothyroxine can indeed cause hair loss, particularly when dosages are not properly managed, leading to conditions like anagen effluvium. Both hypo- and hyperthyroid states can contribute to hair loss, highlighting the importance of maintaining appropriate thyroid hormone levels. Monitoring and adjusting levothyroxine dosage is crucial to prevent and reverse hair loss associated with thyroid hormone imbalances.
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Most relevant research papers on this topic
Diffuse scalp hair loss due to levothyroxine overdose
Levothyroxine overdose can cause diffuse scalp hair loss in infants, but reducing the dose can lead to normal hair growth and no further hair loss.
Case ReportBG02 A case of Werner syndrome: undiagnosed progeroid syndrome presenting as female pattern hair loss
Werner syndrome, an extremely rare autosomal recessive progeroid syndrome, was diagnosed in a 27-year-old woman with female pattern hair loss and other symptoms.
Case ReportThe impact of levothyroxine on thyroid autoimmunity and hypothalamic-pituitary-thyroid axis activity in men with autoimmune hypothyroidism and early-onset androgenetic alopecia.
Levothyroxine therapy benefits men with autoimmune hypothyroidism less pronouncedly in those with early-onset androgenetic alopecia.
Non-RCTLevothyroxine and Non-alcoholic Fatty Liver Disease: A Mini Review.
Levothyroxine may help mobilize hepatic fat and potentially mitigate Non-Alcoholic Fatty Liver Disease (NAFLD) in individuals with underactive thyroid conditions.
Medications and Food Interfering with the Bioavailability of Levothyroxine: A Systematic Review
Many medications and foods can impair the bioavailability of levothyroxine, requiring awareness and dose adjustment for optimal treatment.
Systematic ReviewTyrosine kinase inhibitors causing hypothyroidism in a patient on levothyroxine.
Tyrosine kinase inhibitors can cause hypothyroidism in patients on levothyroxine, leading to fatigue, brittle nails, and oedema.
Case Report
Rigorous JournalOral levothyroxine therapy postbariatric surgery: Biopharmaceutical aspects and clinical effects.
Bariatric surgery may compromise levothyroxine absorption or decrease dose requirements, requiring close monitoring of thyroid hormone levels.
Systematic ReviewHair loss with levetiracetam in five patients with epilepsy
Hair loss may be a rare side effect of levetiracetam treatment in epilepsy patients, but it appears reversible if the dose is reduced or treatment is stopped.
Case ReportSubclinical Hypothyroidism in Pregnancy: A Systematic Review and Meta-Analysis.
Subclinical hypothyroidism during pregnancy increases the risk of adverse maternal and neonatal outcomes, and the value of levothyroxine therapy in preventing these outcomes remains uncertain.
Meta-AnalysisRigorous Journal
Highly CitedEffect of levothyroxine supplementation on pregnancy loss and preterm birth in women with subclinical hypothyroidism and thyroid autoimmunity: a systematic review and meta-analysis
Levothyroxine supplementation significantly decreases pregnancy loss and preterm birth risks in women with subclinical hypothyroidism and thyroid autoimmunity.
Meta-Analysis
Very Rigorous JournalHighly Cited