What Is Congenital Adrenal Hyperplasia?

Congenital adrenal hyperplasia (CAH) is a group of hereditary disorders that affect the adrenal glands. The adrenal glands produce the hormones cortisol and aldosterone. CAH is caused by genetic defects that prevent these glands from producing these two hormones either entirely or at normal rates. Everyone has two of these glands, one on top of each kidney. Cortisol is sometimes called the stress hormone because it’s released when you’re under stress. It helps control blood sugar. Aldosterone helps the kidneys function and balance electrolytes.

The defect that causes CAH is passed down from both parents to their child. According to the National Organization for Rare Diseases, CAH occurs in around one out of every 10,000-15,000 children.

Classical CAH

According to the National Adrenal Diseases Foundation, classical CAH accounts for around 95 percent of all CAH cases. It mainly occurs in infants and young children. The adrenal glands normally produce cortisol and aldosterone with the help of an enzyme known as 21-hydroxylase. With classical CAH this enzyme is missing, which means your adrenal glands can’t make these hormones.

In addition, your body starts making too much of a male sex hormone called testosterone. This causes masculine characteristics to appear in girls and develop early in boys. These characteristics include:

  • being tall for your age
  • having a deep voice
  • early growth of pubic or armpit hair

Although as a child CAH can make you taller than other children, as an adult you could be a little shorter than average.

Nonclassical or Late-Onset CAH

Nonclassical or late-onset CAH is a milder type that occurs in older children and young adults. This type is caused by a partial enzyme deficiency instead of the enzyme being completely absent. If you have this type of CAH, your adrenal glands can make aldosterone, but not enough cortisol. Testosterone levels are also lower in late-onset CAH.

Rare Forms

There are other types of CAH, but they are very rare. These include 11-beta-hydroxylase, 17-alpha-hydroxylase, and 3-beta-hydroxysteroid dehydrogenase deficiencies.

Classical CAH

Infant girls with classical CAH typically have a larger clitoris. Some infant boys have an enlarged penis. Other symptoms in babies include:

  • weight loss
  • poor weight gain
  • vomiting
  • dehydration

Children with classical CAH often go through puberty earlier than normal and also grow faster than other kids but end up being shorter than others in adulthood. Women with this type of CAH usually have irregular menstrual cycles. Both women and men may experience infertility.

Nonclassical or Late-Onset CAH

Occasionally, people with this type of CAH don’t experience any symptoms at all.

Girls and women with late-onset CAH may have:

  • irregular periods or a lack of menstruation,
  • increased facial hair growth
  • deep voice
  • infertility

Some men and women with this type of CAH start puberty early and grow rapidly when they’re young. As with classical CAH, they are usually shorter than average when fully grown.

Other signs and symptoms of nonclassical CAH in men and women include:

  • low bone density
  • severe acne
  • obesity
  • elevated cholesterol

One possible complication of CAH is an adrenal crisis. This is a rare but serious condition, occur in small percentage of individuals who are treated with glucocorticosteroids. Management during illness or stress can be challenging and within hours can result in decreased blood pressure, shock, and death. Signs and symptoms of this condition include:

  • dehydration
  • diarrhea
  • vomiting
  • shock
  • low blood sugar levels

An adrenal crisis requires prompt medical attention.


The most common form of treatment for CAH is taking a replacement hormone medication on a daily basis. This helps bring your affected hormones back up to normal levels and lessens any symptoms.

You might need more than one type of medication or a higher dose of your regular hormone replacement when you’re sick or dealing with excess stress or illness. Both can affect your hormone levels. You can’t outgrow CAH. People with classical CAH will require treatment for the rest of their lives. Nonclassical CAH patients could be symptomatic or non-symptomatic. Symptomatic children should start medication therapy at the first signs of precocoious puberty or bone age acceleration. Adult nonclassical CAH patients might not need treatment when they become adults, as their symptoms may be less noticeable with age.


Girls between the ages of 2 to 6 months can have a surgery called feminizing genitoplasty in order to change the look and function of their genitals. This procedure might need to be repeated when they’re older. According to one study, women who had this procedure are more prone to feeling pain during intercourse or may experience a loss of clitoral sensation later in life.

If you have classical CAH, it’s normal to have concerns about your physical appearance and how your condition affects your sex life. Pain and infertility are also common concerns. Your doctor may be able to refer you to a support group or counselor to help you cope with the condition. Speaking to an unbiased listener or others with the same condition can help you relate and help lessen the emotional issues related to CAH.

If you’re pregnant and CAH runs in your family, you may want to go in for genetic counseling. Your doctor can examine a small piece of your placenta during your first trimester to check for CAH. In your second trimester, your doctor can measure the hormone levels in your amniotic fluid to determine if your baby is at risk. When your baby is born, the hospital can test for classical CAH as part of your newborn’s routine screenings.

If your baby is diagnosed with CAH in utero, your doctor might suggest you take a corticosteroid while you’re pregnant. This type of medication is often used to treat inflammation, but it can also limit the amount of androgens produced by your baby’s adrenal glands. This can help your baby develop normal genitals if she’s a girl, and if your baby is a boy, your doctor will use a lower dose of the same medication for a shorter period of time. This method isn’t widely used because the long-term safety of it for children isn’t clear. It can also cause unpleasant and potentially dangerous side effects in pregnant women, including high blood pressure and mood swings.