What are the physical signs of precocious puberty in boys?

Updated: Nov 30, 2020
  • Author: Paul B Kaplowitz, MD, PhD; Chief Editor: Robert P Hoffman, MD  more...
  • Print
Answer

The earliest sign of CPP is enlargement of the testes, which depends on increased production of follicle-stimulating hormone (FSH); testicular length is more than 2.5 cm, or testicular volume (with Prader orchidometer beads) is 4 mL or more. If progressive signs of androgen excess occur in a boy without increased testicular size, consider possible causes of precocious pseudopuberty, including congenital adrenal hyperplasia, familial male precocious puberty, and Leydig-cell tumors (a testicular nodule is usually palpable). Human chorionic gonadotropin (HCG)–secreting tumors somewhat increase testicular size by stimulating testicular Leydig-cell LH receptors.

Other signs of puberty (eg, penis growth, reddening and thinning of the scrotum, increased pubic hair) are a consequence of increased testosterone production and occur within 1-2 years after testicular enlargement.

Pubic hair growth that occurs without penis and testicular enlargement and other signs of increased androgen production indicate a condition such as premature adrenarche or a mild, nonclassic form of congenital adrenal hyperplasia rather than true puberty.

Later signs of puberty include the pubertal growth spurt, acne, voice change, and facial hair.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!