What is precocious puberty?

Precocious puberty is the term for puberty that begins much earlier than usual. Puberty is the process in which a child has a growth spurt and develops the sexual physical features of an adult.

In the brain, the hypothalamus releases chemicals (hormones) that cause the pituitary gland to release hormones called gonadotropins. Gonadotropins stimulate the growth of the sex glands (also called gonads), which in boys are the testicles, and in girls are the ovaries. In boys, the testicles release testosterone; in girls, the ovaries release estrogen. Puberty usually starts between the ages of 8 and 13 in girls and 9 and 14 in boys.

Children affected by precocious puberty undergo this process much earlier: girls develop secondary sexual characteristics, like breasts, before age 8, and boys with precocious puberty have changes before age 9.

What are the types of precocious puberty?

There are three types of precocious puberty that may affect a child: central precocious puberty (the most common type), peripheral precocious puberty and incomplete puberty.

  • Central precocious puberty: Central precocious puberty occurs when sex hormones are released too early. Central precocious puberty can be caused by brain trauma, tumors of the hypothalamus, or certain infections of the brain. In many cases, especially in girls, the reason for the early release of sex hormones is unknown.
  • Peripheral precocious puberty: Peripheral precocious puberty occurs as a result of problems with reproductive organs (ovaries or testicles) or the adrenal glands, or from hormone exposure from the environment. The adrenal glands are part of the endocrine system and produce hormones the body needs to carry out daily functions. Adrenal glands are located above each kidney and are about the size of a thumb.
  • Incomplete puberty: Incomplete puberty is a condition in which a child has just a few signs of early puberty, such as breast development in very young girls and growth of the body hair in girls or boys. Early body hair can appear when the adrenal glands produce extra androgens.

Who is affected by precocious puberty?

Any child can develop precocious puberty. The condition happens more often in girls than in boys.

How common is precocious puberty?

Early puberty affects an estimated 1 in 5,000-10,000 girls. The incidence of precocious puberty in boys is unknown.

What causes precocious puberty?

Precocious puberty can have different causes, depending on the sex of the child, age of onset, and other factors. In most cases, the causes of central precocious puberty in girls are unknown, but it can be treated effectively.

Precocious puberty at younger ages, and in boys, may be more likely to have an identifiable cause; for instance, if children are exposed to reproductive hormones from sources outside the body, such as from products like estrogen or testosterone creams or other chemicals in the environment.

What are the signs of precocious puberty?

The signs and symptoms of precocious puberty in both boys and girls include acne, body odor and a growth spurt. Precocious puberty also causes sexual characteristics to develop early. In girls, these include:

Early puberty in boys may cause:

  • Deepening voice
  • Facial, pubic and underarm hair
  • Enlargement of the penis and testicles.

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