Objectives: Person-to-person transmission of transdermal testosterone - termed secondary exposure - is a rare but important cause of precocious puberty.
Case presentation: A 3.5-year-old male was evaluated for precocious puberty based on a 6 month history of penile growth, development of secondary sexual characteristics, and growth spurt. Total testosterone level was significantly elevated at 1,460 ng/dL with normal prepubertal gonadotropin levels. Further history revealed that the father had been using transdermal testosterone for about 1 year. Within 2 months of discontinuation, total testosterone level was 20 ng/dL.
Conclusions: Given the recent increase in transdermal testosterone prescriptions, clinicians must consider exogenous hormonal exposure as an etiology for precocious puberty. Prescribers should counsel their patients about the significant risk of secondary exposure.
Keywords: exogenous testosterone exposure; precocious puberty; transdermal testosterone.
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