moon face causes

Moon face, otherwise known as moon facies, is most often caused by Cushing’s syndrome or prolonged steroid treatment and results in an extra fat build-up on the sides of the face.

Moon face, otherwise known as moon facies, is a medical sign characterized by the face developing a rounded appearance due to fat deposits on the sides of the face.

The most common cause of moon face is said to be associated with Cushing's syndrome or prolonged steroid treatment (especially corticosteroids). It can also occur as a symptom of other health conditions, including hypothyroidism. The person’s face shows significant swelling and appears much rounder than usual. The effects of it are most noticeable around the cheeks and chin, making the face appear more “apple-y” and full, hence the term moon face.

What is the pathophysiology of moon facies?

An increased release of hormones, especially cortisol, is a cause of moon face. The adrenal glands, which are triangular-shaped glands located on the top of both kidneys, release excess cortisol that causes increased fat deposition and salt and water retention in the body. The person feels more hungry, resulting in binge eating and fat redistribution.

Moon facies can gradually cause the face to become more round, full or puffy. The sides of the face may become so round from the buildup of fat that the ears can't be seen from the front. Fat deposits over the sides of the skull can also add to making the face look rounder. Moon face may also result from cortisol-secreting tumors or due to prolonged intake of steroid medications.

Conditions associated with moon facies

Conditions that lead to increased cortisol levels (hypercortisolism) are the most common cause of moon face, which includes:

  • Steroid medication is one of the most common causes of moon facies. Prednisone is prescribed for a variety of conditions, such as rheumatoid arthritis or other autoimmune conditions because it helps reduce swelling and inflammation. However, long-term use of this medication can cause adverse effects, such as redistribution of fat deposits in some people. This leads to fat accumulation in specific parts of the body, including the face, abdomen and back of the neck.
  • Cushing’s syndrome is a condition that occurs when the body produces too much of the hormone cortisol. The increased cortisol level also increases the deposition of fat around the face, giving it the shape of the moon.
  • Increased release of a hormone, adrenocorticotropic hormone (ACTH), from the pituitary gland also prompts the adrenal gland to produce cortisol.
  • Nonpituitary tumors, such as tumors of the lung, pancreas or thymus, may also cause big releases of ACTH.
  • Benign tumors or cancers in the adrenal gland.

How is moon facies diagnosed?

To confirm moon facies as a result of abnormal cortisol levels, the doctor may suggest blood and urine tests. Confirming the cause of high cortisol levels may require other tests, such as magnetic resonance imaging (MRI) or computed tomography (CT) scan.

How is moon facies treated?

The treatment for moon face depends on the cause, but may include:

  • When the moon face is caused by prednisone or another steroid, the simplest treatment is often to reduce the dosage. Over time, being on a lower dose will reduce the appearance of the moon face. Never stop or decrease the dosage of medications without consulting the doctor.
  • Managing hypothyroidism with thyroxine supplements may help treat moon face.
  • Avoid foods high in salt because they can worsen the moon face.
  • Have a healthy diet and adequate physical activity to manage weight.
  • Treatment of underlying conditions (such as cortisol-producing tumors) may be needed.

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Medically Reviewed on 8/16/2021
References
Nguyen HCT. Endogenous Cushing Syndrome. Medscape. https://emedicine.medscape.com/article/2233083-overview

Nguyen HCT. Iatrogenic Cushing Syndrome. Medscape. https://emedicine.medscape.com/article/117365-overview