Congenital Adrenal Hyperplasia Can Look Like PCOS

An Overview of Congenital Adrenal Hyperplasia Symptoms That Mimic PCOS

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When considering a diagnosis of Polycystic Ovary Syndrome (PCOS), it is normal for a doctor to consider Late Onset Congenital Adrenal Hyperplasia (CAH) as a possible culprit. This is because these two diseases often present the same symptoms.

Late Onset Congenital Adrenal Hyperplasia (CAH)

Congenital Adrenal Hyperplasia (CAH) is an inherited group of diseases where a key enzyme is missing from the body.

Genetic defects present at the time of birth (congenital) affect several enzymes needed to produce vital adrenal cortex hormones.

Almost 95% of CAH cases are caused by a lack of the enzyme 21-hydroxylase. The body cannot make adequate amounts of two key adrenal steroid hormones—cortisol and aldosterone—when enzyme 21-hydroxylase is missing or functioning at low levels. This throws off the delicate balance of hormones, preventing the proper synthesis of aldosterone and cortisol, and the adrenal cortex starts to make androgens (male steroid hormones) leading to masculine traits in females. In this classical form of CAH, salt balance can also be drastically altered, leading to electrolyte imbalances, dehydration and cardiac rhythm changes.

While many patients are diagnosed shortly after birth, there is a type of this disease which develops later in life, usually in adolescence or early adulthood, called non-classical or Late-Onset CAH.

These patients are missing only some of the enzymes necessary for cortisol production, aldosterone production is not affected, so this form of the disease is less severe than the congenital form and shows symptoms that are often mistaken for PCOS, such as:

  • Premature development of pubic hair
  • Irregular menstrual periods
  • Hirsutism (unwanted or excess body hair)
  • Severe acne (on the face and/or body)
  • Fertility problems in 10-15% of young women with CAH

Diagnosis of CAH

Congenital adrenal hyperplasia is transmitted genetically, with Eastern European Jews (Ashkenazi) having an increased risk of having this disease as compared to the general population. Since it is an autosomal recessive disease, both parents must carry a defective enzyme trait to pass it on to their child.

Due to the genetic transmission of the condition, many patients are aware of the risk in their family and let their doctor know of the need for genetic screening. The doctor may run urine and blood tests to look for abnormal cortisol levels, or other hormonal levels. Increased androgen levels may also be considered when making a diagnosis. A thorough family history record and physical exam are also necessary for the doctor to make a complete diagnosis.

Treatment Options

Birth control pills are usually effective in regulating the menstrual cycle, decreasing acne and sometimes abnormal hair loss. If this is not effective in dealing with symptoms, or the doctor feels that birth control pills are not appropriate for you, she may consider low dose steroid treatment.

However, treatment is not typically lifelong.

For patients with classical CAH with an aldosterone deficiency a drug like fludrocortisone (Florinef) that acts like the missing hormone will retain salt in the body. Infants also receive supplemental salt (as crushed tablets or solutions), whereas older patients with classical forms of CAH eat salty foods.

The specific drug and regimen is usually up to the discretion of the treating physician and is dependent on the severity of symptoms.


Migeon, Claude J. and Wisniewski, Amy B. Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency: A guide for patients and their families. Johns Hopkins Hospital, Department of Pediatrics and Department of Endocrinology. Prepared 22 May 01.

National Adrenal Diseases Foundation. Congenital Adrenal Hyperplasia (CAH). 

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