DESCRIPTION

• Breast development in girls <8 years of age without evidence of sexual hair development, vaginal mucosa estrogenization, linear growth acceleration, rapid bone maturation, adult body odor, or behavioral changes
• Exaggerated thelarche, a variant of isolated breast development, occurs without axillary or pubic hair but with some acceleration of growth and bone maturation, and increased uterine size.
• Data suggest that African American girls may develop pubertal changes as early as 6 years of age and Caucasian girls as early as 7 years of age. However, caution should be used when evaluating children because signs of puberty at these younger ages may not be considered normal and may be due to pathologic conditions.

EPIDEMIOLOGY

• 60–85% of cases are noted between 6 months and 2 years of age.
• There is no one identifiable group of girls who develops early thelarche.

RISK-FACTORS

Unknown

PATHOPHYSIOLOGY

• Transient increases in follicle-stimulating hormone levels causing follicular ovarian development.
• Low levels of estrogen secretion by normal follicular cysts
• Increased sensitivity of breast tissue to low levels of estrogen
• Delay in inhibition of the “minipuberty” of infancy
• Exposure to exogenous estrogen (e.g., cosmetic and hair products, lavender oil, infant formulas containing soy, xenoestrogens, and polybrominated diphenyl ethers)