Precocious puberty
Typically, puberty begins around age 10 in girls, and age 12 for boys. But in precocious puberty, pubertal changes begin early — before age 8 in girls and before age 9 in boys. Although early puberty can be a normal variation, it can sometimes be a sign of an underlying health problem, so it is important for the child to see a pediatric endocrinologist.
There are some consequences of precocious puberty including earlier timing of a growth spurt and achievement of final height. When the onset of puberty occurs early, the process of bone maturation ends earlier as well. So, children with early puberty may be tall for their age at the time of puberty but may mature into short adults.
Other risks include emotional problems brought on by the difficulties of dealing with physical changes that occur earlier than one's peers. Additionally, early puberty may, at times, be initiated by processes which require treatment to prevent other ill effects.
Signs of precocious puberty (prior to age 8 in girls and prior to age 9 in boys):
In girls:
In boys:
- Enlargement of the testicles or penis
- Facial hair development
- Voice changes
In both boys and girls:
- Acne
- Adult body odor
- Pubic or underarm hair growth
- Rapid growth
Causes of precocious puberty
First, it is important to understand what triggers normal puberty. The hypothalamus, pituitary, and gonads (ovaries in girls and testicles in boys) are involved in a pathway of hormones that, when activated, result in rising levels of in estrogen in girls and testosterone in boys.
The hypothalamus produces gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) which then stimulate the production of sex hormones (estrogen or testosterone) in the gonads (ovaries or testicles).
The adrenal glands separately produce testosterone-like hormones in both boys and girls that are more involved in development of pubic and axillary hair.
Most commonly, there is no identifiable cause of precocious puberty. Additionally, being overweight or obese can contribute to early maturation of body development.
In rare cases precocious puberty may be due to:
- A structural problem in the brain (such as an abnormal growth or mass)
- Brain injury due to head trauma
- An infection (such as meningitis or encephalitis)
- A problem in the ovaries, testes, adrenal or thyroid gland
- A genetic disease affecting endocrine organs, bones, and skin
For the majority of girls, there is no underlying medical problem; they simply start puberty too early for no known reason. In boys, the condition is less common, and more likely to be associated with an underlying medical problem than it is in girls.
Types of precocious puberty
- Central precocious puberty, also known as gonadotropin-dependent precocious puberty, involves early activation of hormones from the hypothalamus and pituitary.
- Peripheral precocious puberty, also known as gonadotropin-independent precocious puberty is not related to the early release of hormones from the hypothalamus and pituitary, but reflects hormone production by the gonads (ovaries or testes) or adrenals.
Premature adrenarche is considered a separate condition from precocious puberty and refers to early development of pubic or axillary hair, body odor, and acne. It most commonly occurs as a result of slightly early activation of adrenal hormones rather than involvement of hormones from the hypothalamus-pituitary-gonads. Rare abnormal causes of early adrenarche include an enzyme deficiency in the adrenal gland (congenital adrenal hyperplasia) and a mass in the adrenal gland.
How precocious puberty is diagnosed
While precocious puberty can be upsetting to children and parents alike, it may not require treatment. It depends on the underlying cause, which is why a thorough work-up by a pediatric endocrinologist is important.
In addition to a complete medical history and physical examination, tests to define the diagnosis typically include:
- An x-ray of the hand and wrist (bone age) to determine the level of maturation of the growth centers
- Blood tests to measure hormone levels
If there are concerns that certain hormones are elevated, further studies may be obtained:
- An ultrasound of the adrenal glands or the ovaries or testes
- An MRI to take detailed images of structures within the body or brain
- A hormone stimulation test to determine the form of precocious puberty
Treatment for precocious puberty
The kind of treatment will depend on the cause found on evaluation and on factors such as:
- The child's age, overall health, and medical history
- The extent of the condition
- The child's ability to tolerate certain medications, procedures or therapies as mentioned above
The goal of treatment is to suppress or slow the rate of pubertal changes. Central precocious puberty can be effectively treated with medication involving, most typically, a monthly injection or a yearly implant (surgical placement underneath the skin of a tube containing slowly released medication) that suppresses the signals from the hypothalamus-pituitary until the medication is stopped.
If necessary, counseling may help the child cope with the emotional effects of early puberty.