Congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a group of inherited genetic conditions that limits the adrenal glands' ability to make certain vital hormones.


Congenital adrenal hyperplasia (CAH) refers to a group of genetic disorders that affect the adrenal glands, a pair of walnut-sized organs above the kidneys. The adrenal glands produce important hormones, including:

  • Cortisol, which regulates the body's response to illness or stress
  • Mineralocorticoids, such as aldosterone, which regulate sodium and potassium levels
  • Androgens, such as testosterone, which are male sex hormones required for growth and development in both males and females

In people who have CAH, a gene change (mutation) results in a lack of one of the enzymes needed to make these hormones.

The two major types of congenital adrenal hyperplasia are:

  • Classic CAH. This rarer, more-severe form is usually detected at birth or in early infancy.
  • Nonclassic CAH. This form is milder and more common. It may not be identified until childhood or early adulthood.

Although there is no cure, with proper treatment, most people who have CAH. can lead full lives.

Adrenal glands

Located on top of each kidney, the adrenal glands make hormones that help regulate metabolism, the immune system, blood pressure and other important functions. Although small, these glands control much of what happens in the body.


Signs and symptoms of CAH vary, depending on which gene is affected and the level of enzyme deficiency. The imbalance of hormones the body needs to function may mean too little cortisol, too little aldosterone, excess androgens or a combination of these imbalances.

Classic CAH

Signs and symptoms of classic CAH may include:

  • Insufficient cortisol. Classic CAH causes the body to produce an insufficient amount of cortisol. This can cause problems maintaining normal blood pressure, blood sugar and energy levels, and cause problems during physical stress such as illness.
  • Adrenal crisis. People with classic CAH can be seriously affected by a lack of cortisol, aldosterone or both. This is known as an adrenal crisis, and it can be life-threatening.
  • Atypical genitalia. Female infants may have atypical genitalia appearance, such as an enlarged clitoris that may resemble a penis, and a partially closed labia resembling a scrotum. The urinary opening (urethra) and the vagina may be only one opening instead of two separate openings. The uterus, fallopian tubes and ovaries usually develop typically.

    Male infants usually have typical-appearing genitals.

  • Excess androgen. An excess of the male sex hormone androgen can result in short height and early puberty for both males and females. Pubic hair and other signs of puberty may appear at a very early age. Severe acne also may occur.

    Excess androgen hormones in females may result in facial hair, excessive body hair and a deepening voice.

  • Altered growth. Rapid growth may occur during childhood with an advanced bone age. Final height may be shorter than average.
  • Fertility issues. These can include irregular menstrual periods, or not having any at all, and having infertility problems in females. Fertility issues can sometimes occur in males.

Nonclassic CAH

Often there are no symptoms of nonclassic CAH when a baby is born. Some people with nonclassic CAH never have symptoms. The condition is not identified on routine infant blood screening and usually becomes evident in late childhood or early adulthood. Cortisol may be the only hormone that's deficient.

Females who have nonclassic CAH may have typical-appearing genitals at birth. Later in life, they may experience:

  • Irregular menstrual periods, or not having any at all, and problems getting pregnant
  • Masculine characteristics such as facial hair, excessive body hair and a deepening voice

In both females and males, signs of nonclassic CAH may also include:

  • Early appearance of pubic hair and other signs of early puberty
  • Severe acne
  • Rapid growth during childhood with an advanced bone age and shorter than expected final height

When to see a doctor

Classic CAH is usually detected at birth through routine newborn screening or when babies have atypical genitalia. CAH may also be identified when male or female babies show signs of severe illness due to low levels of cortisol, aldosterone or both.

In children who have nonclassic CAH, signs and symptoms of early puberty may appear. If you have concerns about your child's growth or development, make an appointment with your child's health care provider.

If you are pregnant and may be at risk of CAH because of your own medical history or your ethnicity, ask your health care provider about genetic counseling.


The most common cause of CAH is the lack of the enzyme known as 21-hydroxylase. CAH may sometimes be called 21-hydroxylase deficiency. This enzyme is required by the body to make proper amounts of hormones. There are other much rarer enzyme deficiencies that also cause CAH.

CAH is a genetic disorder, which means it's inherited from parents and is present at birth. Children who have the condition have two parents who either have CAH themselves or who are both carriers of the genetic change that causes the condition. This is known as the autosomal recessive inheritance pattern.

Autosomal recessive inheritance pattern

In an autosomal recessive disorder, two changed genes are inherited, one from each parent. The parents' health is rarely affected because they have only one changed gene. Two carriers have a 25% chance of having an unaffected child with two unaffected genes. They have a 50% chance of having an unaffected child who also is a carrier. They have a 25% chance of having an affected child with two changed genes.

Risk factors

Factors that increase the risk of having CAH include:

  • Parents who both have CAH or are both carriers of the genetic change for the disorder
  • Being of Ashkenazi Jewish, Latino, Mediterranean, Yugoslav or Yup'ik ancestry


People who have classic CAH are at risk of adrenal crisis. This is a life-threatening medical emergency that requires immediate treatment. Adrenal crisis can occur within the first few days after birth. It can also be triggered at any age by infectious illness or physical stress such as surgery.

Very low levels of cortisol in the blood can cause diarrhea, vomiting, dehydration, low blood sugar levels, seizures and shock. Aldosterone also may be low, which leads to dehydration and low sodium and high potassium levels. The nonclassic form of CAH doesn't cause adrenal crisis.

People who have either classic or nonclassic CAH may experience fertility problems.


There is no known way to prevent CAH. If you're thinking of starting a family and you're at risk of having a child with CAH, your health care provider may recommend that you see a genetic counselor.


Congenital adrenal hyperplasia (CAH) may be diagnosed before a baby is born, shortly after birth, during childhood or later in life.

Prenatal testing

Tests used to identify CAH in fetuses who are at risk for the disorder include:

  • Amniocentesis. This procedure involves using a needle to withdraw a sample of amniotic fluid from the womb and then examining the cells.
  • Chorionic villus sampling. This test involves withdrawing cells from the placenta for examination.

Tests to confirm the diagnosis of CAH are done after the baby is born.

Newborns and infants

In the United States and many other countries, routine screening of all newborns for genetic 21-hydroxylase deficiency is recommended during the first few days of life. This test identifies the classic form of CAH but doesn't identify the nonclassic form.

In female infants who have severe atypical genitalia, tests can be done to analyze chromosomes to identify genetic sex. Also, pelvic ultrasound can identify the presence of female reproductive structures such as the uterus and ovaries.

Children and young adults

Diagnosis of CAH in children and young adults includes:

  • Physical exam. Your health care provider will do a physical exam, check your child's blood pressure and heart rate, and review symptoms to identify possible CAH. The next step is to confirm the diagnosis with blood and urine tests.
  • Blood and urine tests. These tests look for hormones produced by the adrenal glands at levels outside the standard ranges. The tests also check the levels of electrolytes. These are minerals such as sodium that balance the amount of water in the body.
  • Genetic testing. Genetic testing may be needed to diagnose CAH.


Your health care provider will likely refer your child to a specialist in childhood hormonal issues (pediatric endocrinologist) for treatment of CAH. The health care team may also include other specialists, such as a urologist, psychologist, gynecologist and geneticist.

Treatment may include medications, reconstructive surgery and psychological support.


The goal of treating CAH with medications is to reduce excess androgen production and replace deficient hormones. People who have the classic form of CAH can successfully manage the condition by taking hormone replacement medications throughout their lives.

People who have nonclassic CAH may not require treatment or may need only small doses of corticosteroids.

Medications for CAH are taken daily. During periods of illness or significant stress, such as surgery, additional medications or higher doses may be needed.

Medications may include:

  • Corticosteroids to replace cortisol
  • Mineralocorticoids to replace aldosterone to help retain salt and get rid of excess potassium
  • Salt supplements to help retain salt

Monitoring the effectiveness of medication includes regularly scheduled:

  • Physical exams. The health care provider will check your child's growth and development, including monitoring changes in height, weight, blood pressure and bone growth. Assessing health at regular visits is lifelong.
  • Monitoring for side effects. The health care provider will monitor for medication side effects, such as the loss of bone mass and impaired growth, particularly if steroid-type replacement medication doses are high and used long term.
  • Blood tests to check hormone levels. It's critical to have regular blood tests to ensure that hormone levels are balanced. Children who haven't yet reached puberty need enough cortisone to suppress androgens to grow to a typical height. For females who have CAH, it's important to suppress androgens to minimize unwanted masculine characteristics. On the other hand, too much cortisone can cause Cushing syndrome.

Wearing a medical identification tag can help provide appropriate treatment if there's an emergency.

Reconstructive surgery

In some female infants who have severe atypical genitalia because of classic CAH, health care providers may recommend reconstructive surgery to improve genital function and provide a more typical appearance.

Surgery may involve reducing the size of the clitoris and reconstructing the vaginal opening. The surgery is typically performed between 2 and 6 months of age. Females who have reconstructive genital surgery may need more cosmetic surgery later in life.

Genital surgery is easier to perform when a child is very young. However, some parents choose to wait for surgery until their child is old enough to understand the risks and choose the gender assignment.

Before making decisions about the best treatment approach for your child, talk with your health care provider about these issues. Working together, you and your provider can make informed choices that will help your child thrive.

Psychological support

Psychological support is important to the emotional health and social adjustment of children and adults who have CAH.


Prenatal treatment with synthetic corticosteroids that cross the placenta to the fetus are controversial and considered experimental. More research is needed to determine the long-term safety and the effect of this treatment on fetal brain development.

Coping and support

Early and steady support from family and health care professionals can help your child have healthy self-esteem and a satisfying social life. These approaches may help:

  • Include psychological counseling in your child's treatment plan as needed
  • Seek help from a mental health professional if you're having trouble coping and to help you develop healthy parenting strategies

Preparing for an appointment

You may start by seeing your family health care provider or your child's pediatrician. Your provider may refer you to a specialist trained in the diagnosis and treatment of conditions related to the adrenal glands (pediatric endocrinologist).

Here's some information to help you prepare for your appointment. Consider taking a family member or friend along for support and to help you remember information.

What you can do

To prepare for your appointment:

  • Find out if your child needs to follow any pre-appointment restrictions, such as changing food or liquid intake to get ready for blood and urine tests.
  • Make a list of any signs and symptoms your child has been experiencing, and for how long.
  • Make a list of your child's key medical information, including recent illnesses, any medical conditions, and the names and dosages of any medications, vitamins, herbs or other supplements.
  • Prepare questions you want to ask your health care provider.

Some basic questions to ask may include:

  • What is likely causing my child's signs and symptoms?
  • Are there other possible causes for these symptoms?
  • What kinds of tests does my child need?
  • What treatment approach do you recommend?
  • What are the expected results of treatment?
  • What are the possible side effects of treatment?
  • How will you monitor my child's health over time?
  • What is my child's risk of long-term complications?
  • Do you recommend that my child receive psychological counseling?
  • Do you recommend that our family meet with a genetic counselor?

Don't hesitate to ask any other questions during your appointment.

What to expect from your doctor

Your health care provider is likely to ask you a number of questions, such as:

  • What are your child's symptoms?
  • When did you first begin noticing these symptoms?
  • Has anyone in your family been diagnosed with congenital adrenal hyperplasia? If so, do you know how it was treated?
  • Are you planning to have more children?

Be ready to answer questions to reserve time to go over points you want to focus on.

© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. | Terms of Use