Pubarche

Pubarche is the appearance of pubic hair in children. It is one of the physical signs of puberty. While often associated with the activation of the hypothalamic-pituitary-gonadal (HPG) axis and the onset of true puberty, isolated pubarche can occur independently due to increased adrenal androgen production.

Causes:

Pubarche can be caused by:

• Adrenarche: Increased production of adrenal androgens, such as dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS), without activation of the HPG axis. This is the most common cause of isolated pubarche.
• Premature adrenarche: Early activation of the adrenal glands leading to increased androgen production.
• True precocious puberty: Early activation of the HPG axis, leading to the development of other secondary sexual characteristics in addition to pubic hair.
• Androgen-secreting tumors: Rare tumors in the adrenal glands or ovaries that produce androgens.
• Congenital adrenal hyperplasia (CAH): A genetic condition affecting the adrenal glands, leading to overproduction of androgens.
• Exogenous androgen exposure: Exposure to external sources of androgens, such as creams or medications.

Diagnosis and Evaluation:

Evaluation of pubarche typically involves:

• Physical examination: Assessing the stage of pubic hair development (Tanner staging) and looking for other signs of puberty (e.g., breast development, testicular enlargement).
• Medical history: Gathering information about the child's growth, development, and family history of puberty.
• Hormone testing: Measuring levels of DHEA, DHEAS, testosterone, LH, and FSH to determine the source of the androgens and assess HPG axis activity.
• Bone age assessment: X-ray of the left wrist to assess skeletal maturation.
• Imaging studies: In some cases, imaging studies such as an ultrasound or CT scan may be performed to evaluate the adrenal glands and ovaries.

Management:

Management of pubarche depends on the underlying cause.

• Isolated adrenarche: In most cases, no specific treatment is required for isolated adrenarche. The child should be monitored for signs of progressive puberty.
• True precocious puberty: Treatment may involve medications to suppress the HPG axis and slow down the progression of puberty.
• Androgen-secreting tumors or CAH: Treatment may involve surgery, medication, or hormone replacement therapy.

See also:

• Adrenarche
• Precocious Puberty
• Puberty
• Tanner Stages