Congenital adrenal hyperplasia (CAH) is a genetic condition that affects the adrenal glands. Learn about CAH, including its symptoms, diagnosis, and treatment.

What Is Congenital Adrenal Hyperplasia?

Congenital adrenal hyperplasia (CAH) is an inherited (genetic) condition that affects the adrenal glands. The adrenal glands are small glands on top of the kidneys. They make the following important hormones:

  • Cortisol is the hormone your body makes under stress. It is important for regulating energy and maintaining normal blood pressure and blood sugar. Our bodies make high amounts of cortisol to help us deal with the stress of illness.
  • Aldosterone helps balance the levels of salt and water in the body. It also helps maintain blood pressure.
  • Androgens are sex hormones that help with pubertal changes and certain male physical characteristics. Both boys and girls make androgens.

How Does CAH Affect the Body?

In CAH, the adrenal glands are missing part of or all an enzyme (typically 21-hydroxylase). This enzyme helps make cortisol. When almost no enzyme is available, the adrenal glands might not make enough aldosterone as well. Because of the missing enzyme and the low cortisol level, the pituitary gland in the brain makes higher amounts of another hormone called ACTH, which tries to push the adrenal gland to make more cortisol. In this process, the adrenal glands make higher levels of androgens, a process not affected by the absence of this enzyme. The high androgen levels can cause changes in the genital area.

What Are the Symptoms of CAH?

Symptoms of CAH depend on your child’s age:


Newborn babies may have a life-threatening condition called “adrenal crisis.” Adrenal crisis can have the following symptoms:

  • Vomiting
  • Severe dehydration
  • Low blood pressure
  • Low blood sugar
  • Shock
  • Abnormal sodium and potassium levels

In females, the genitals might look more like male genitals.

In males, the genitals may look darker than expected.

In a less severe form (simple virilizing CAH), genital findings are present without salt (sodium and potassium) abnormalities.

Older children

When CAH is diagnosed later in life, it is usually a milder form of the condition. This is called Non-classic (late onset) CAH. You might notice the following signs:

  • Body odor, armpit hair or pubic hair before age 8 (in girls) or age 9 (in boys)
  • Early growth spurt
  • Early puberty

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Rev. 3/2020. Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.