Classic Congenital Adrenal Hyperplasia: Causes, Symptoms, Treatments

Medically Reviewed by Dan Brennan, MD on May 09, 2024
6 min read

Congenital adrenal hyperplasia (CAH) is a condition passed down through your family that affects the body’s adrenal glands. These glands sit on top of the kidneys and make three critical hormones that help the body work properly:

Cortisol. Helps the body handle stress and regulates blood pressure, energy, and sugar levels

Aldosterone. Controls salt and water levels, as well as blood volume and pressure

Androgens. Testosterone is the main form of these hormones. They start puberty and support normal growth and development. 

CAH is a condition in which a gene that tells the body how to make an enzyme called 21-hydroxylase, which helps make cortisol and aldosterone, doesn't work properly. For you to have CAH, both of your parents need to carry the faulty gene and pass it on to you.

Classic CAH

There are different types of congenital adrenal hyperplasia, including one called classic CAH. While it’s less common than the other types, it’s more serious and can be deadly if left untreated. People with classic CAH face health problems related to their adrenal glands, such as shock and coma. 

There are two subtypes of classic CAH:

Salt-wasting CAH. With this most serious form of CAH, the adrenal glands don’t make enough aldosterone. Low levels of the hormone throw off your body’s sodium (salt) levels, causing you to lose too much sodium when you pee. This can lead to dehydration and even death. The condition also triggers the body to make too much androgen and not enough cortisol.

Simple virilizing CAH. This form of CAH also affects aldosterone, cortisol, and androgen, but the hormone imbalance is more moderate than with salt-wasting CAH.

High levels of androgens in the body cause a range of symptoms, mostly related to sex development. They include:

  • External genitals that look typically male and internal reproductive organs that are usually female in babies assigned female at birth (AFAB)
  • A larger penis in babies assigned male at birth (AMAB)
  • Early signs of puberty (body and facial hair growth, voice changes, and severe acne)
  • Male traits in people AFAB (large muscles, a deep voice, and excess facial hair)
  • Fast growth
  • Irregular menstrual periods
  • Noncancerous tumors of the testicles
  • Trouble conceiving a baby (infertility)
  • Short height as an adult

Salt-wasting CAH can cause serious adrenal symptoms (called an “adrenal crisis”) such as:

  • A loss of body fluid (dehydration)
  • Low levels of blood sodium (hyponatremia)
  • Low blood pressure (hypotension)
  • An irregular heartbeat (arrhythmia)
  • Low blood sugar
  • A buildup of acid in your body (metabolic acidosis)
  • Throwing up
  • Diarrhea
  • Weight loss
  • Shock

During pregnancy

If you’re pregnant and already have a child with CAH, think about getting prenatal testing. Your doctor will check for the condition with one of these tests:

Amniocentesis. After 15 weeks of pregnancy, your doctor removes a sample of amniotic fluid from your uterus and then sends it to a lab to test for various conditions. 

Chorionic villus sampling (CVS). During this test, at 10 to 13 weeks of pregnancy, your doctor removes a small sample of cells from your placenta to test for CAH and other conditions.

Newborns and infants

Before your newborn leaves the hospital, their doctor will do a blood test to screen for classic CAH by pricking their heel. The test checks for a lack of 21-hydroxylase.

Children and adults

In kids and adults, there are several ways to confirm CAH:

Physical exam. Your doctor will check your child’s blood pressure and heart rate and ask about their symptoms. 

Blood and urine tests. If your child has CAH, their electrolyte and certain hormone levels may be outside the normal range. Tests of their blood and pee will check these levels.

X-ray. This test checks whether your child’s bones are developing faster than expected. 

Genetic testing. This type of testing will confirm whether CAH is causing your child’s symptoms.

There’s no cure for CAH, but the right treatment plan could ease your child’s symptoms. Treatment for classic CAH involves a combination of medication, watching for symptom and hormone changes, and possibly surgery.

Classic CAH medications

Your child may need one or more prescription drugs to treat their symptoms, which they’ll take every day for life. They include:

  • Salt (sodium chloride) supplements to replace lost sodium
  • Cortisol or glucocorticoids (hydrocortisone, prednisone, or dexamethasone) to replace cortisol that the body is unable to make on its own. They’ll need higher doses of these when they’re sick, injured, or stressed (called “stress doses”).
  • Mineralocorticoids to make up for the lack of aldosterone in the body

Classic CAH monitoring

With monitoring, your child will have routine blood tests to check their hormone levels. Doctors will also check your child’s height, weight, bone age, and sexual development. As they mature, they’ll transition to doctors for adults, including endocrinologists (doctors who treat hormone problems) and infertility specialists.

You and your doctor will also watch for changes in your child’s symptoms caused either by CAH or by taking certain medicines to treat it. Undertreatment or overtreatment of the condition can cause:


  • Early puberty
  • Short height as an adult
  • Irregular menstrual periods
  • Acne
  • Excessive hair growth (hirsutism) in people AFAB
  • Masses on the testicles of people AMAB


  • Slow growth
  • Too much weight gain
  • Osteoporosis
  • High blood pressure (hypertension)

Classic CAH surgery

Babies AFAB may need surgery on their external genitals to correct how they look and function. This involves reducing the size of the clitoris and reconstructing the vaginal opening.

This surgery usually happens when they’re around 6 months old but may take place earlier or later than this age. Some parents decide to wait until their child is old enough to decide for themselves whether or not they want surgery.

Before the operation, you’ll meet with a urologist and a surgeon, who will discuss your options and the pros and cons of the operation.

Other classic CAH therapies

Other treatments and therapies for classic CAH include:

  • Therapies to delay puberty
  • Screening for fertility issues
  • Birth control pills to regulate periods
  • Nutrition and mental health counseling

New CAH treatments

Several new CAH treatments are on the horizon, most of which help control the body’s hormone levels. Researchers are studying:

  • Medicines that release glucocorticoids slowly over time (called modified release), which mimic how the body naturally makes hormones
  • Glucocorticosteroids delivered under the skin all the time using a small pump
  • Treatments that target the HPA-axis, a system involved in regulating hormones
  • Gene and cell-based therapies to fix the enzyme problem responsible for hormone imbalances

Classic CAH clinical trials

Some hospitals do clinical trials to test treatments for CAH and related health problems, such as early puberty or growth disorders.

If your child loses a lot of water and salt in their pee from having CAH, they have a higher chance of other health problems, including:

  • Electrolyte imbalance
  • Irregular heartbeat (arrhythmia)
  • Cardiac arrest

Genital correction surgery also comes with potential issues like infection, bleeding, and scarring.

Before your doctor’s appointment, you may want to write down a list of questions to ask, such as:

  • What form of CAH does my child have? 
  • Should we visit a specialist?
  • Which tests does my child need?
  • Does my family need genetic testing?
  • What are our treatment options?
  • How could treatment help?
  • What are the pros and cons of these treatments?
  • What are the possible side effects of treatment?
  • How will you track my child’s health over time?

With early diagnosis and consistent medication, your child can live a healthy life with CAH. They’ll need to take daily medication for the rest of their life to manage symptoms. Stopping can cause symptoms to come back. While most people with CAH are generally healthy, your child might be shorter than others and could face fertility issues.

Support for classic CAH

Mental health support can help you or your child to manage CAH’s social and emotional challenges. When looking for a mental health professional, focus on those experienced in supporting people with CAH.

Living with classic CAH

Your child could have a medical emergency related to their condition at some point. That’s why taking steps now is important to keep them safe. Here are some ideas:

Emergency injection kit. Keep this kit on hand in case your child’s hydrocortisone levels drop. It should have:

  • Hydrocortisone vials and vial snaps
  • Syringes
  • Instructions on how to give a hydrocortisone shot
  • Emergency information (contacts, medical history, and medications)

Caregivers should learn how to give a hydrocortisone shot before an emergency happens.

Steroid card. If your child uses steroids, they should also carry a steroid card to let medical professionals know to continue steroid treatment and to give them more during an illness or emergency. You can find downloadable steroid cards online.

Medical ID jewelry. A medical bracelet or necklace helps to quickly share critical medical information with first responders, paramedics, and doctors.