Precocious puberty and pseudoprecocious puberty are sexual maturation that begins before age 9 in a boy or before age 7 or 8 in a girl.
True precocious puberty is caused by the early release of certain sex hormones (gonadotropins) from the pituitary gland. These hormones cause the ovaries or testes to develop and begin secreting other sex hormones, such as estrogen or testosterone, which trigger puberty. This early hormone release may be caused by a tumor or other abnormality in the pituitary gland or the hypothalamus (the region of the brain that controls the pituitary gland). Neurofibromatosis (a disorder where many fleshy growths of nerve tissue grow under the skin and in other parts of the body) and a few other rare disorders also have been linked to precocious puberty.
In pseudoprecocious puberty, high levels of testosterone or estrogen are produced by a tumor or other abnormality in the adrenal gland or in a testis or ovary. These hormones do not cause the testes or ovaries themselves to mature but do trigger secondary sex characteristics to develop, including pubic and underarm hair, adult body odor, acne, and changes in body shape. Boys develop facial hair, their penis lengthens, and they take on a masculine appearance. Girls develop breasts and may begin to menstruate, particularly in true precocious puberty. In both sexes, the growth spurt may be triggered, leading to a rapid height increase. This rapid height increase ends early, ultimately leaving these adolescents shorter as adults than would be expected.
In true precocious puberty, the sex glands (ovaries or testes) also mature and enlarge, whereas in pseudoprecocious puberty, the sex glands remain immature. Precocious puberty is 10 times more common among and much more likely to be of unknown cause (idiopathic) among girls.
Whenever a child has signs of premature, rapidly progressing, or disordered puberty, doctors take an x-ray of the hand and wrist to estimate bone maturity. If a child's bone age is very advanced, a more complete evaluation usually is indicated. Tests may include blood hormone levels to determine a cause, an ultrasound of the pelvis and adrenal glands to check for ovarian or adrenal tumors, and computed tomography or magnetic resonance imaging of the head to check for tumors of the hypothalamus or pituitary gland.
Treatment is not needed for children who have only premature pubic and underarm hair growth or breast development, but regular reexamination is needed to check for later development of precocious puberty.
Treating an identifiable cause of precocious puberty, such as removing a tumor or cyst, may stop the progression of puberty. When no treatable cause is identified, drugs may slow the progression of puberty. Injections of a synthetic gonadotropin-releasing hormone (such as leuprolide acetate, deslorelin, or histrelin) may stop true precocious puberty by stopping the production of sex hormones. Pseudoprecocious puberty can be stopped by drugs that inhibit the action of the sex hormones.
Last full review/revision January 2009 by Sharon Levy, MD, MPH