Congenital adrenal hyperplasia (CAH) is usually detected through a routine blood test in newborns or prenatal testing, allowing lifesaving treatment to begin right away. However, it’s still important to recognize the symptoms. Keeping an eye out for signs of CAH can help ensure your baby’s treatment is working properly.

You may know that CAH is a genetic condition that affects the adrenal glands, which are small organs on top of the kidneys that produce hormones. It disrupts hormones like aldosterone, androgens, and cortisol. But what you may not know is how that affects daily life.

If you’re unsure what to look for or want a handy list that’s easy to access, you’re in the right place. Here’s what you should look for when it comes to CAH symptoms in your newborn. The following symptoms are most common in classic CAH (also called salt-wasting CAH). Classic and nonclassic CAH make up 95 percent of CAH cases. Nonclassic CAH doesn’t usually develop until later in childhood, during adolescence, or adulthood.

1. Vomiting

Vomiting is common in newborns with CAH, but it can be hard to tell the difference between vomiting and normal spit-up. Spit-up usually comes out easily with a burp, while vomit tends to be more forceful. This difference can be tricky to spot, especially for first-time parents or if you haven’t seen a baby spit up before. If you’re unsure, reach out to your pediatrician or pediatric endocrinology team, a group of doctors who specialize in hormone-related conditions in children, for guidance.

2. Diarrhea

Diarrhea is a common symptom of CAH in newborns, but it can be hard to recognize because newborn stool (poop) is often loose and can change frequently in the first few weeks. Signs of diarrhea include more frequent bowel movements and changes in color, texture, or consistency. If your baby’s diet hasn’t changed and you think they may have diarrhea, see your pediatrician or pediatric endocrinologist to find out what’s going on.

3. Dehydration

Vomiting and diarrhea can lead to dehydration. CAH can also cause your baby to lose too much sodium and water through their urine, which can result in dangerously low fluid levels. A dehydrated newborn may have dry eyes, dry skin, and a dry mouth. The soft spot in the center of their skull might look sunken. If you press on their thumbnail until it turns pale, it should turn red again quickly — if it takes more than two seconds, this may be a sign of dehydration. These warning signs mean you should get your baby to a healthcare provider right away.

4. Not Eating Well

Newborns living with CAH may not eat very much or very well. Poor feeding can happen whether your baby is breastfed or given formula. It may be related to the same discomfort that causes vomiting and diarrhea. There are several reasons why a newborn might not eat well. If your child isn’t eating well after a CAH diagnosis or has other symptoms from this list, talk to a doctor to find out what to do next.

5. Variations in Genital Appearance

Many newborns with CAH may have genitalia that look different from what is typically expected for their age and gender. Female babies may have ovaries, a uterus, and fallopian tubes internally but have external genitalia that look different from typical female anatomy. For example, the labia may resemble a scrotum because it might appear partly closed, the clitoris may be enlarged and look more like a penis, or there may be one hole instead of two for the urethra (where you urinate) and vagina. Male babies may have a penis that is larger than expected at birth.

These changes are more likely to be present at birth in newborns with classic CAH, but they can also appear in another form of CAH, nonclassic CAH, especially in female babies. This is one reason why doctors and nurses check a newborn’s genitals after birth. If they notice any changes, they can make sure the infant gets the tests they need to figure out what is going on. While these tests are usually part of a standard newborn screening test, this double-checking can ensure your child gets the treatment they need if they have CAH.

6. Low Blood Sugar

CAH may also cause low blood sugar levels in your newborn. It may take a blood test to figure out if your newborn has low blood sugar because some won’t have any symptoms. However, a baby with low blood sugar may experience shaking or tremors, bluish skin, issues staying warm, breathing problems, floppy muscles, irritability, and feeding difficulty. If your newborn shows any signs that their blood sugar is too low, get care immediately.

7. Low Blood Sodium

A newborn with CAH may also have very low sodium (salt) levels in their blood. This happens because their body can’t produce the hormones needed to control sodium levels. Low sodium is called hyponatremia and may cause vomiting, seizures, or unusual muscle weakness. Sodium levels are usually measured with a blood test, which your baby’s pediatric or endocrinology team will order if they suspect a problem.

8. Weight Loss

Weight loss is also common in babies diagnosed with CAH. This is beyond the normal weight loss that babies experience after birth. If your baby doesn’t gain this weight back within two weeks or continues to lose weight, talk to their healthcare team right away. If they’re being treated for CAH, they may need additional treatment. If your baby hasn’t been diagnosed, it’s time to run some tests.

9. Shock

Some infants living with CAH will go into shock, which is what happens when their brain and other organs aren’t getting enough blood flow. In newborns with CAH, this is called an adrenal crisis, and it’s an emergency. A baby experiencing an adrenal crisis may have a very rapid heart rate, be extremely irritable, or go into a coma. If you suspect your baby is in shock or is headed that way, call for emergency help immediately. Shock is life-threatening and needs to be treated as quickly as possible.

10. High Blood Acid Levels

Metabolic acidosis (high blood acid levels) is usually diagnosed with a blood test. Your newborn may have a very fast heart rate, experience changes in their breathing that sound and feel different, seem weaker than usual, have breath that smells fruity or sweet, stop eating, or start vomiting. All of these are signs that it’s time to get medical care as soon as possible to reverse this condition and help your baby feel better.

Early Support Is Key

Recognizing CAH symptoms early can make a big difference in your baby’s health. If you notice anything concerning, talk to your doctor as soon as possible. With the right care and monitoring, babies with CAH can grow and thrive. Early treatment helps manage symptoms and supports healthy development.

Talk With Others Who Understand

On CAHteam, the site for people with congenital adrenal hyperplasia and their loved ones, people come together to gain a new understanding of CAH and share their stories with others who understand life with the condition.

What symptoms of congenital adrenal hyperplasia have you noticed in your newborn? Are there any that your baby didn’t experience? Share your insights in the comments below.