Very early or late onset of puberty, usually due to a hormonal imbalance
- Occurs before or after the normal age range for puberty
- Sometimes runs in families; rarely due to a chromosomal abnormality
- Excessive exercise and a poor diet may be risk factors in some cases
The natural process of sexual development and maturation that takes place over several years is known as puberty. In boys, puberty is normally characterized by enlargement of the genitals; development of hair on the face, in the armpits, and in the pubic region; a growth spurt, in which the body gets bigger and more muscular; and deepening of the voice. Puberty in boys usually begins between the ages of 10 and 14. Abnormal puberty starts either earlier than normal (precocious puberty) or later (delayed puberty).
Precocious puberty is rare and is usually an indication of an underlying hormonal disorder. Delayed puberty is more common and less likely to indicate a serious underlying condition.
What are the causes?
In boys, puberty is controlled by male sex hormones produced by the testes and adrenal glands. The production of these hormones is controlled by hormones from the pituitary gland and from the hypothalamus (the part of the brain that regulates the pituitary gland). Disorders in these organs may lead to abnormal early or late puberty.
Precocious puberty is caused by the overproduction of male sex hormones in a young boy. For example, congenital adrenal hyperplasia, in which the adrenal glands produce excessive amounts of male sex hormones, may lead to precocious puberty.
Boys in whom puberty is delayed are usually just late developers, a tendency that often runs in families. However, delayed puberty may also be caused by the underproduction of male sex hormones. Rarely, there is a more serious underlying cause, such as a brain tumour pressing on the hypothalamus or pituitary gland, or a chromosome disorder, such as Klinefelter’s syndrome, in which the sex organs do not develop normally. Some long-term illnesses, such as Crohn’s disease, kidney failure, cystic fibrosis, and diabetes mellitus, can also cause delayed puberty and growth. Certain lifestyle factors, such as excessive exercise and an inadequate diet, may delay the onset of puberty. Rarely, a pituitary tumour may lead to either precocious or delayed puberty.
What might be done?
Early or late puberty should be investigated by a doctor, who will carry out a physical examination to see if puberty has started or how far it has progressed. A blood test may also be performed to measure hormone levels and to check for a chromosomal abnormality. X-rays of the wrist and hand may be used to assess bone maturity, and ultrasound scanning of the testes or adrenal glands may also be carried out to look for abnormalities. If a pituitary tumour is suspected, MRI or CT scanning may be performed.
If tests identify an underlying cause for abnormal puberty, it will be treated. For example, precocious puberty may be treated with drugs that block the production of male sex hormones or inhibit their action. These drugs may be given in the form of injections, implants under the skin, or nasal sprays. If delayed puberty runs in the family, treatment may not be needed. In many other cases, puberty is induced by giving injections of testosterone (see Sex hormones and related drugs). Some boys benefit from counselling for psychological problems caused by abnormal puberty.
Abnormal puberty is often treatable, but lifelong treatment may be needed. Future fertility depends on the cause.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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