Precocious puberty is when a child's body begins changing into that of an adult (puberty) too soon. When puberty begins before age 8 in girls and before age 9 in boys, it is considered precocious puberty.

Puberty includes rapid growth of bones and muscles, changes in body shape and size, and development of the body's ability to reproduce.

The cause of precocious puberty often can't be found. Rarely, certain conditions, such as infections, hormone disorders, tumors, brain abnormalities or injuries, may cause precocious puberty. Treatment for precocious puberty typically includes medication to delay further development.

Precocious puberty signs and symptoms include development of the following before age 8 in girls and before age 9 in boys.

• Breast growth and first period in girls
• Enlarged testicles and penis, facial hair and deepening voice in boys
• Pubic or underarm hair
• Rapid growth
• Acne
• Adult body odor

When to see a doctor

Make an appointment with your child's doctor for an evaluation if your child has any of the signs or symptoms of precocious puberty.

To understand what causes precocious puberty in some children, it's helpful to know what causes puberty to begin. The brain starts the process with the production of a hormone called gonadotropin-releasing hormone (GnRH).

When this hormone reaches the pituitary gland — a small bean-shaped gland at the base of your brain — it leads to the production of more hormones in the ovaries for females (estrogen) and the testicles for males (testosterone).

Estrogen is involved in the growth and development of female sexual characteristics. Testosterone is responsible for the growth and development of male sexual characteristics.

Why this process begins early in some children depends on whether they have central precocious puberty or peripheral precocious puberty.

Central precocious puberty

The cause for this type of precocious puberty often can't be identified.

In central precocious puberty, the puberty process starts too soon. The pattern and timing of the steps in the process are otherwise normal. For the majority of children with this condition, there's no underlying medical problem and no identifiable reason for the early puberty.

In rare cases, central precocious puberty may be caused by:

• A tumor in the brain or spinal cord (central nervous system)
• A defect in the brain present at birth, such as excess fluid buildup (hydrocephalus) or a noncancerous tumor (hamartoma)
• Radiation to the brain or spinal cord
• Injury to the brain or spinal cord
• McCune-Albright syndrome — a rare genetic disease that affects bones and skin color and causes hormonal problems
• Congenital adrenal hyperplasia — a group of genetic disorders involving abnormal hormone production by the adrenal glands
• Hypothyroidism — a condition in which the thyroid gland doesn't produce enough hormones

Peripheral precocious puberty

Estrogen or testosterone in your child's body causes this type of precocious puberty.

The less common peripheral precocious puberty occurs without the involvement of the hormone in your brain (GnRH) that normally triggers the start of puberty. Instead, the cause is release of estrogen or testosterone into the body because of problems with the ovaries, testicles, adrenal glands or pituitary gland.

In both girls and boys, the following may lead to peripheral precocious puberty:

• A tumor in the adrenal glands or in the pituitary gland that releases estrogen or testosterone
• McCune-Albright syndrome, a rare genetic disorder that affects the skin color and bones and causes hormonal problems
• Exposure to external sources of estrogen or testosterone, such as creams or ointments

In girls, peripheral precocious puberty may also be associated with:

• Ovarian cysts
• Ovarian tumors

In boys, peripheral precocious puberty may also be caused by:

• A tumor in the cells that make sperm (germ cells) or in the cells that make testosterone (Leydig cells).
• A rare disorder called gonadotropin-independent familial sexual precocity, which is caused by a defect in a gene, can result in the early production of testosterone in boys, usually between ages 1 and 4.

Factors that increase a child's risk of precocious puberty include:

• Being a girl. Girls are much more likely to develop precocious puberty.
• Being African-American. Precocious puberty appears to affect African-Americans more often than children of other races.
• Being obese. Children who are significantly overweight have a higher risk of developing precocious puberty.
• Being exposed to sex hormones. Coming in contact with an estrogen or testosterone cream or ointment, or other substances that contain these hormones (such as an adult's medication or dietary supplements), can increase your child's risk of developing precocious puberty.
• Having other medical conditions. Precocious puberty may be a complication of McCune-Albright syndrome or congenital adrenal hyperplasia — conditions that involve abnormal production of the male hormones (androgens). In rare cases, precocious puberty may also be associated with hypothyroidism.
• Having received radiation therapy of the central nervous system. Radiation treatment for tumors, leukemia or other conditions can increase the risk of precocious puberty.

Possible complications of precocious puberty include:

• Short height. Children with precocious puberty may grow quickly at first and be tall, compared with their peers. But, because their bones mature more quickly than normal, they often stop growing earlier than usual. This can cause them to be shorter than average as adults. Early treatment of precocious puberty, especially when it occurs in very young children, can help them grow taller than they would without treatment.
• Social and emotional problems. Girls and boys who begin puberty long before their peers may be extremely self-conscious about the changes occurring in their bodies. This may affect self-esteem and increase the risk of depression or substance abuse.

Some of the risk factors for precocious puberty, such as sex and race, can't be avoided. But, there are things you can do to reduce your child's chances of developing precocious puberty, including:

• Keeping your child away from external sources of estrogen and testosterone — such as prescription medications for adults in the house or dietary supplements containing estrogen or testosterone
• Encouraging your child to maintain a healthy weight

To diagnose precocious puberty, the doctor will:

• Review your child's and your family's medical history
• Do a physical exam
• Run blood tests to measure hormone levels

X-rays of your child's hand and wrist also are important for diagnosing precocious puberty. These X-rays can help the doctor determine your child's bone age, which shows if the bones are growing too quickly.

Determining the type of precocious puberty

Your child's doctor will also need to find out which type of precocious puberty your child has. To do so, he or she will perform a test called a gonadotropin-releasing hormone (GnRH) stimulation test.

In this test, the doctor will take a blood sample, and then give your child a shot containing the GnRH hormone. More blood samples are then taken over a certain period of time to check how hormones in your child's body react. In children with central precocious puberty, the GnRH hormone will cause other hormone levels to rise. In children with peripheral precocious puberty, other hormone levels stay the same.

Additional testing for central precocious puberty

• Magnetic resonance imaging (MRI). A brain MRI is usually done for children who have central precocious puberty to see if any brain abnormalities are causing the early start of puberty.
• Thyroid testing. The doctor may also test your child's thyroid if he or she shows any signs of slow thyroid function (hypothyroidism), such as fatigue, sluggishness, increased sensitivity to cold, constipation, a drop in school performance or pale, dry skin.

Additional testing for peripheral precocious puberty

Other tests also are necessary for children with peripheral precocious puberty to find the cause of their condition. For example, the doctor may run additional blood tests to check other hormone levels or, in girls, he or she may do an ultrasound to check for an ovarian cyst or tumor.

The primary goal of treatment is to enable your child to grow to a normal adult height.

Treatment for precocious puberty depends on the cause. However, in some cases, there is no identifiable cause for precocious puberty. In this instance, your child may not need treatment depending on his or her age and how rapidly puberty is progressing. Your child's doctor may want to monitor your child for several months to see how he or she is developing.

Treating central precocious puberty

Most children with central precocious puberty, in which there's no underlying medical condition, can be effectively treated with medication. This treatment, called GnRH analogue therapy, usually includes a monthly injection of a medication, such as leuprolide acetate (Lupron Depot), or triptorelin (Trelstar, Triptodur Kit), which delays further development. Some newer formulations can be given at longer intervals.

The child continues to receive this medication until he or she reaches the normal age of puberty. On average, 16 months after he or she stops receiving the medication, the process of puberty begins again.

Another treatment option for central precocious puberty is a histrelin implant (Supprelin LA), which lasts for up to a year. This treatment is effective for central precocious puberty without the pain and inconvenience of regular injections, but it does require a minor surgical procedure. The implant is placed under your child's skin through an incision in the inner area of the upper arm. After a year, the implant is removed and, if necessary, replaced with a new implant.

Treating an underlying medical condition

If another medical condition is causing your child's precocious puberty, treatment of that condition is necessary to stop the progress of puberty. For example, if a child has a tumor that's producing hormones and causing precocious puberty, puberty usually will stop when the tumor is surgically removed.

Children who begin puberty early may feel different from their peers. Although there are few studies on the emotional effects of precocious puberty, it's possible that feeling different can cause social and emotional problems, including early sexual experimenting. As a parent, you also may have trouble dealing with your child's early development.

If you, your child or other members of your family are having difficulty coping, seek counseling. Psychological counseling can help your family better understand and handle the emotions, issues and challenges that accompany precocious puberty. If you have questions or would like guidance on how to find a qualified counselor, talk with a member of your health care team.

You're likely to start by seeing your child's pediatrician or a family doctor. Or you may be referred immediately to a doctor who specializes in the treatment of hormone-related conditions in children (pediatric endocrinologist).

Here's some information to help you get ready for your appointment and know what to expect from your child's doctor.

What you can do

• Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your child's diet.
• Write down your child's symptoms, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medications, vitamins or supplements that your child takes or that others in the home take — because your child may have had access to them.
• Make a list of family members' heights, especially if any of them are short as adults.
• Write down your family medical history, and note if any family members have had precocious puberty or endocrine problems.
• Bring a copy of your child's growth curve record if you are visiting a new doctor who doesn't have access to your child's medical record.
• Write down questions to ask your child's doctor.

List questions for your child's doctor to help make the most of your time together. For precocious puberty, some basic questions to ask your doctor include:

• What is likely causing my child's symptoms or condition?
• Are there other possible causes for my child's symptoms or condition?
• What tests does my child need?
• Is this condition likely temporary or chronic?
• What's the best treatment?
• When should treatment begin, and how long will it last?
• What are the alternatives to the primary approach you're suggesting?
• My child has other health conditions. How can we best manage them together?
• Are there restrictions my child needs to follow?
• Should my child see a specialist?
• Is there a generic alternative to the medicine you're prescribing?
• Are there brochures or other printed material I can take home? What websites do you recommend?

Don't hesitate to ask any other questions you have.

What to expect from your doctor

Your doctor is likely to ask you a number of questions about:

• Your family medical history, in particular, family members' heights and any history of endocrine disorders or tumors
• The age at which puberty began for siblings and parents
• Family racial composition