Precocious Puberty Differential Diagnoses

Updated: Jan 24, 2022
  • Author: Paul B Kaplowitz, MD, PhD; Chief Editor: Robert P Hoffman, MD  more...
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Diagnostic Considerations

Premature adrenarche

Premature adrenarche (also referred to as premature pubarche) refers to the early appearance of pubic hair, axillary hair, or both in children without other signs of puberty. [34] An adult-type axillary body odor is the other major clinical finding. Signs of severe androgen excess (eg, clitoral enlargement, growth acceleration, severe acne) should prompt further investigation to exclude a rare virilizing tumor or a variant form of congenital adrenal hyperplasia.

The etiology of premature adrenarche is an earlier than usual increase in the secretion of weak androgens by the adrenal gland. Although regulation of adrenal androgen secretion is poorly understood, it is distinct from that of gonadal steroids. Therefore, early appearance of pubic hair may not temporally correlate with the appearance of breast development and is generally not a cause for concern. It is common practice to obtain a bone age in such patients to exclude a more serious disorder, but since bone age is often advanced by 2 years or more, the value of the bone age in this setting may be questioned. [35]

Premature thelarche

Premature thelarche is the appearance of breast development in young girls in the absence of other signs of precocious puberty (eg, growth acceleration, changes in uterine size and vaginal mucosa). It is typically seen in girls aged 3 years or younger. [36]  Breast tissue normally seen in the newborn period due to maternal estrogens can persist for a year or more in some infants. The keys to making this diagnosis include the following:

  • Observing that the child is growing in length along her established percentile channel
  • Noting that the amount of breast tissue increases only minimally over time (or may even decrease)
  • Observing a lack of thickening and pigmentation of the nipples and the areola as seen in girls with precocious puberty

The etiology of this condition is unknown. In some cases, small ovarian cysts that transiently produce estrogens may be responsible. In Puerto Rico, an epidemic of premature thelarche in the 1970s was suspected to have been caused by exposure to estrogens in poultry. Despite a lack of firm evidence, phytoestrogens in soy products and other environmental estrogen-like agents (eg, pesticides, phthalates) may have the potential to cause breast development in young children. Certain essential oils, in particular lavender-fragranced products commonly used in Hispanic communities, have been linked to early breast development, which resolves when exposure is discontinued. [37]

Prepubertal vaginal bleeding

When a girl with little or no breast development has vaginal bleeding, this causes great concern for parents and providers. This condition, sometimes referred to as "premature menarche," has been well-described in the literature, although its cause is unknown. Studies show that hormonal levels are prepubertal, and pelvic ultrasonography shows a prepubertal uterus and ovaries. [38]  The bleeding can occur monthly but resolves in a few months, so reassurance and watchful waiting are often the best course. In persistent cases, a foreign body such as toilet paper may be found on pelvic exam. 

Exogenous androgens

Exposure to exogenous sex hormones is an occasional cause of early puberty (eg, pubic hair, phallic enlargement). The most common etiology in young children has been inadvertent exposure to androgens through contact with adult males who use topical androgens such as AndroGel. Asking about such potential exposure is important because the problem resolves rapidly when such exposure ceases. [39]

Differential Diagnoses