Frey’s Syndrome: Causes, Symptoms, Diagnosis, and Treatment

frey's syndrome icd causes and treatment

It is a rare disorder that consists of gustatory sweating and facial flushing.

Frey’s Syndrome, also known as Baillarger’s Syndrome, is a potential complication of the procedure known as parotidectomy, which is the removal of a portion of an essential salivary gland.

This complication likely starts because of damage to the auriculotemporal nerve which is the result of an injury to the parotid glands.

When this nerve heals, it reattaches to sweat glands instead of the original salivary gland. That means when the patients should salivate, they sweat instead.

Redness and sweating appear whenever the patient eats or desires foods that produce strong salivation.

Frey’s Syndrome Causes

Medical experts are not entirely sure about the exact underlying cause of this condition.

Several researchers theorize that Frey’s Syndrome occurs because of simultaneous damage to sympathetic and parasympathetic nerves near the parotid glands.

Parasympathetic nerves are part of a portion the nerve system that regulates involuntary body functions. These nerves can control the activity of salivary glands, but they cannot control sweat glands.

The Sympathetic nerves are the ones that help to regulate or control sweat glands, as well as blood vessels.

Some medical experts believe that the parasympathetic and sympathetic nerves, located in the region of the face or neck, are cut.

These very same researchers claim that while this happens, small branches of the auriculotemporal nerve get severed.

Such nerves can regenerate on their own, but in Frey’s Syndrome, the damaged nerves heal abnormally by growing along the sympathetic nerves, connecting them to the small sweat glands in the skin.

So, the parasympathetic nerves that send the signals to produce salivation mistakenly send the same command to these sweat glands.

That is why patients who suffer from Frey’s Syndrome find their bodies responding with excessive sweating and flushing when they consume food.

The damage or injury that causes the nerves to regenerate abnormally can occur due to a wide variety of reasons.

But the most common cause known by doctors is parotidectomy.

Some reliable sources suggest that at the very least half of the cases of patients suffering from Frey’s Syndrome underwent parotidectomy.

A least common cause is suffering blunt force trauma in the area of the auriculotemporal nerve.

Another rare cause may be damage to the central sympathetic nerve chain in the neck.


More often than not, patients develop the first signs of Frey’s Syndrome within the first year after surgery.

In some cases, they might not develop this condition until several years after the parotidectomy.

The primary symptom of Frey’s Syndrome is gustatory sweating (excessive sweating on the cheeks, forehead, and around the ears after eating).

Other symptoms related to this condition include flushing and a sensation of warmth in the affected areas.

Some patients who suffer from this disorder sometimes complained of a feeling of pain. But several experts believe that such thing occurs because of the surgery, not because of the condition.

Several factors such as the affected area, the size of that area, and the amount of sweating/flushing vary significantly from case to case.


To accurately diagnose this condition, doctors need to base their conclusions on the identification of most typical symptoms, detailed patient history, clinical evaluation and the Minor Iodine-Starch Test.

The Minor Iodine-Starch Test is a diagnostic procedure meant to evaluate sudomotor functions; it consists of applying an iodine solution to the affected areas of the face.

After applying this solution to the skin, medical experts allow it to air-dry.

When the skin is dry, healthcare providers apply cornstarch or potato flour over the affected area.

Doctors will provide patients with stimuli to sweat, and when the sweat mixes with the starch powder and the iodine solution, it gets discolored until turning purple.

Frey’s Syndrome Treatment

The standard therapies get oriented to relieving the symptoms. Some people use medications that hinder the production of sweat, or topical drugs that block specific functions of the nervous system.

But when patients are looking for a more permanent solution, reconstructive surgery is their only option.

If the surgeon is good enough, the treatment might even reduce facial scars and correct facial deformities left by other surgical procedures.

However, most surgeons are not capable of such feats because this treatment is a hazardous procedure.

That is why most medical experts prefer to prescribe drugs and medications to alleviate or suppress the symptoms.