Precocious pubertyBMJ 2020; 368 doi: https://doi.org/10.1136/bmj.l6597 (Published 13 January 2020) Cite this as: BMJ 2020;368:l6597
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Bradley et al suggest that enlargement of the penis and growth of pubic hair in a young boy represent red flags because, as reported in table 2 of the article, some of these patients may have serious underlying pathology, including intracranial, adrenal or testicular tumors. The differential diagnosis, however, should also mention the possibility of passive androgen transfer from skin to skin contact.
In 2010 Mason et al reported in the BMJ the case of a 4 year old boy with penile enlargement (Tanner stage G4) and pubic hair development (Tanner stage P4) whose father had been receiving testosterone gel 50 mg daily for post-surgical hypopituitarism. The child had been sleeping in the parents bed for 6 months, and discontinuation of skin to skin contact with the father resulted in regression of the problem (1). This report follows other published cases (2,3,4), and regulatory authorities recommend avoiding skin contact with gel application sites to prevent testosterone transfer to other people, particularly pregnant women and children (5,6).
Taking a careful drug history from family members of children presenting with sexual precocity may avoid unnecessary testing and prevent the residual genital enlargement and advanced bone age reported in few cases (1).
(1) Mason A, McNeil E, Wallace AM et al. Sexual precocity in a 4 year old boy. BMJ 2010; 340 : c2319.
(2) Yu YM, Punyasavatsu N, Elder D et al. Sexual development in a two-year-old boy induced by topical exposure to testosterone. Paediatrics 1999; 104 : e23
(3) Kunz GJ, Klien KO, Clemons RD et al. Virilisation of young children after topical androgen use by their parents. Paediatrics 2004; 114 : 282-4
(4) Brachet C, Vermeulen J, Heinrichs C. Children’s virilization and the use of a testosterone gel by their fathers. Eur J Pediatr 2005; 164 : 646-7
(5) Voelker R. Childrens’s exposure to testosterone gel spurs FDA to order boxed label warning. JAMA 2009; 301:2428.
(6) British National Formulary 78 (September 2019-March 2020) : 768
Competing interests: No competing interests