Alternative Names sexual precocity, precocious puberty
Definition Puberty is a time when the body changes and is able to reproduce for the first time. Precocious puberty is when these changes occur earlier than normal.
What is going on in the body? The primary sexual changes that occur during puberty are the growth and maturation of the ovaries in girls and the testicles in boys. The secondary changes are the development of the breasts, sexual hair, widening of the pelvis in girls and increase in muscle mass in boys.
Puberty begins when a hormone called gonadotropin (GnRH) is released from an area at the base of the brain. Gonadotropin is carried to the pituitary gland. It causes the pituitary glands to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In females, LH and FSH stimulate the ovaries to make the hormone, oestrogen. In males, they stimulate the testes to make the hormone, testosterone. Precocious puberty occurs when this process begins early. This is also called central precocious puberty or CPP. It also can occur if other stimuli trigger early sex hormone production or release. This is called peripheral precocious puberty or PPP. With CPP, sexual changes occur in the normal sequence seen in puberty. With PPP, this sequence can vary.
Partial forms of precocious puberty are fairly common. The most common forms involve premature development of the breasts in girls, or isolated, premature development of sexual hair in girls or boys.
Premature thelarche is the early development of breast tissue without any other signs of sexual maturity. It occurs in the first 2 years of life and lasts about 3 to 5 years. It rarely progresses any further. Menstruation occurs at the usual age and reproductive capacity is not affected. It is usually a benign condition but may be the first sign of true precocious puberty. Girls with premature thelarche should be followed and evaluated if they show other signs of sexual maturation or accelerated growth.
Premature adrenarche refers to the appearance of sexual hair prior to age 8 in girls and age 9 in boys, without other signs of maturation. This occurs much more often in girls than in boys. It is also more common in African American children. It is usually a benign condition. Rarely, it can be a sign of a form of congenital adrenal hyperplasia, or overgrowth of tissue in the adrenal gland, which may require treatment. Girls with premature adrenarche may develop polycystic ovary disease, which means multiple cysts develop on the ovary, as adults.
Some girls develop premature menarche. This is when menstrual periods begin earlier than usual, without other signs of puberty. Usually these girls have only 1 to 3 early periods. Once these periods end these girls go on to have a normal puberty and menstrual cycles. This is less common than premature thelarche or adrenarche.
What are the signs and symptoms of the disease? Puberty is called precocious in African American girls if they develop breasts before they are 5 or 6 years old. It is called precocious in Caucasian girls if they develop breasts before they are 6 or 7 years old. African American and Caucasian boys both start puberty at about 9 years old. Puberty is called precocious for them if they begin sexual changes before this time. Precocious puberty is much more common in girls than it is in boys.
Children with CPP grow more rapidly than normal. Children with isolated, partial forms of precocious puberty, on the other hand, usually grow normally.
In normal male puberty and in male CPP, the testicles enlarge before the penis begins to enlarge. In PPP, the penis grows much larger than the testicles.
Mental development is usually the same as other children their age. Mood swings are not uncommon, but serious psychological problems are unusual.
What are the causes and risks of the disease? Precocious puberty can be caused by:
small growths in the brain
structural defects or tumour of the brain
hydrocephalus, a disorder where there is an abnormal amount of spinal fluid in the brain
severe head trauma
cranial radiation, where the brain is exposed to X-rays
severe epilepsy, a central nervous system disorder causing seizures
This disease can also be inherited. The risk in a family where one parent carries the gene gives a 50 percent risk that male infants would be affected. This disease also carries a 50 percent risk that female infants would be carriers of the gene with each pregnancy.
Often no cause can be found.
Oestrogen can cause premature sexual changes, like breast development, that can look like precocious puberty. Oestrogens are found in:
hair and body creams
certain meats, like poultry
These precocious changes go away after the oestrogen exposure is stopped.
What can be done to prevent the disease? Precocious puberty cannot be prevented.
How is the disease diagnosed? Precocious puberty is first diagnosed when a doctor or parent notices secondary sexual changes. Further testing includes:
What are the long-term effects of the disease? Some forms of this disease cause the skeleton to mature quickly. At first, these children are taller than their peers. But, because the skeletal maturation is advanced, growth stops early for these children. They end up being very short adults.
Because their growth and sexual development is advanced, some children with precocious puberty may feel isolated from their peer group until the maturation of the peer group catches up with them. Parents and teachers need to have age-appropriate rather than appearance-appropriate expectations of these children in terms of their behaviour.
What are the treatments for the disease? Children with CPP whose bone age is 2 years more advanced than their chronological age can be treated with long-acting GnRH agonists. These are given by injection every 3 to 4 weeks. These injections cause sexual development to stop and normal growth rate to return. Girls can be given this treatment until they are between 11 and 12 years old. Boys can be given this treatment until they are between 12 and 13 years old.
Children who have precocious puberty for reasons other than CPP need to have the primary disorder treated. This can include:
removal of a tumour
cortisol treatment of congenital adrenal hyperplasia, which is overgrowth of the adrenal gland tissue, or thyroid hormone replacement for those with hypothyroidism
specialised medications to treat McCune-Albright syndrome, which is a disorder caused by ovarian cysts in children. This results in brown spots on the skin along with precocious puberty
Children with premature thelarche or adrenarche need to be followed by a doctor, but do not need treatment.
What are the side effects of the treatments? Some girls with CPP will have vaginal bleeding about 2 weeks after the first injection of a GnRH agonist. This usually does not occur after this.
How is the disease monitored? Children with this disease should be monitored by a paediatric endocrinologist and paediatrician.
Author: John Wegmann, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 17/02/2005 Contributors Potential conflict of interest information for reviewers available on request
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