Precocious Puberty

Background

• Precocious puberty is the appearance of secondary sex characteristics prior to normal age for pubertal development due to increased sex hormone production or exposure.
• This can lead to increased linear growth, somatic development, and more rapid skeletal maturation.
• Commonly used age cutoffs in the United States for early pubertal development are before age 8 years in girls and 9 years in boys. Cutoffs may vary according to country and ethnicity.
• Precocious puberty can be classified as central precocious puberty (CPP) or peripheral precocious puberty (PPP).
  • In central precocious puberty, increased sex hormone production is caused by early activation of the hypothalamic-pituitary gonadal axis.
  • Peripheral precocious puberty is caused by increased sex hormones from gonads, adrenal glands, ectopic production from germ cell tumor, or exogenous sex steroid exposure.
• Benign variants of puberty can also occur, including premature thelarche and premature adrenarche.
• The main complications of precocious puberty are dramatically accelerated development for age and premature attainment of foreshortened adult height. Psychosocial issues related to early development may also occur.

Evaluation

• The diagnosis of precocious puberty starts with the history and physical exam.
  • Isolated nonprogressive breast development in girls, especially toddlers, may be simple premature thelarche.
  • Pubic hair and/or axillary hair and no breast development in girls or pubic/axillary hair and no testicular enlargement in boys is likely to be premature adrenarche.
  • Clinical findings that suggest a pathologic cause include rapid progression, advanced development, rapid linear growth, advanced skeletal maturation, testicular growth in boys, and the development of breasts in girls.
• Check bone age x-ray of hand and wrist to assess skeletal maturation.
• Laboratory testing to determine the cause of precocious puberty should start with basal levels of gonadotropins and sex steroids to help distinguish CPP from PPP.
  • Early morning gonadotropin levels may detect elevations if midday gonadotropins are prepubertal and CPP remains suspected.
  • If gonadotropin levels are still inconsistent with the physical exam, assessment of luteinizing hormone (LH) after stimulation with gonadotropin-releasing hormone (GnRH) analog (stimulation test) may be necessary to diagnose CPP.
  • GnRH stimulation test may be performed if basal gonadotropin levels do not match the clinical examination; however, this testing is rarely needed with the use of ultrasensitive immunochemiluminescence assays for gonadotropins.
• Additional laboratory testing may include serum adrenal steroids to distinguish between PPP and benign adrenarche, human chorionic gonadotropin (hCG) to rule out ectopic sources of sex hormones, and thyroid function studies to rule out primary hypothyroidism as the underlying cause of precocious puberty.
• Additional imaging tests that may help detect underlying abnormalities and causes of precocious puberty include magnetic resonance imaging of the brain and pituitary with and without contrast and ultrasound of the pelvis.

Management

• Refer children with suspected precocious puberty to a pediatric endocrinologist for further evaluation and possible treatment.
• The treatment approach varies by type of precocious puberty.
  • For CPP, GnRH analogs are the mainstay of treatment.
  • For PPP, treat the underlying disease or cause.
  • No treatment is required for benign variants of puberty (premature thelarche and premature adrenarche) since they are self-limited conditions.
• Evaluating for precocious puberty can be performed during well-child examinations by noting pubertal milestones and growth chart patterns.