Precocious puberty

[Sonia]

Precocious puberty is onset of sexual maturation before age 8 in girls or age 9 in boys. Diagnosis is by comparison with population standards, x-rays of the left hand and wrist to assess skeletal maturation and check for accelerated bone growth, and measurement of serum levels of gonadotropins and gonadal and adrenal steroids. Treatment depends on the cause.
In girls, the first pubertal milestone is typically breast development (thelarche), followed soon after by appearance of pubic hair (pubarche) and axillary hair and later by the first menstrual period (menarche), which traditionally occurs 2 to 3 years after thelarche (see Figure: Puberty—when female sexual characteristics develop).
In boys, the first pubertal milestone is typically testicular growth, followed by penile growth and appearance of pubic and axillary hair (see Figure: Puberty—when male sexual characteristics develop).
In both sexes, appearance of pubic and axillary hair is called adrenarche. Adrenarche may occur before gonadarche in about 10% of children (premature adrenarche). Although gonadarche and adrenarche may have overlapping signs, they are regulated independently.
The definition of precocious puberty depends on reliable population standards for onset of puberty (ie, when pubertal milestones occur); because onset seems to be occurring earlier in the US, especially in females, these traditional standards are being reevaluated. Breast development is increasingly occurring at younger ages and this trend is mirroring the obesity epidemic, with a higher body mass index (gt; 85th percentile) associated with earlier thelarche.
Almost 8 to 10% of white girls, 20 to 30% of black girls, and an intermediate percentage of Hispanic girls reach early puberty at age 8. The lower limit of normal puberty may be 7 years for white girls and 6 years for black girls. The mean age for early breast development is about 9.5 to 10 years for white girls and 8.5 to 9 years for black girls (range 8 to 13 years). However, the age of menarche has not lowered as drastically, with a mean decrease of only 3 months in the past 30 years (mean age 11.5 years in black girls and 12.5 years in white girls). The mean age for pubic hair growth is 9 to 10.5 years for both groups. These findings imply that guidelines for evaluating disorders that cause precocious puberty can be interpreted more leniently if children are otherwise healthy and are projected to reach their full adult height potential.