Introduction and Overview

Frey syndrome is also known as auriculotemporal syndrome or Baillargers syndrome.¹ It is a rare² disorder that occurs due to injury or surgical intervention near the parotid gland. It affects the auriculotemporal nerve, a branch of the trigeminal nerve.

The auriculotemporal nerve has parasympathetic fibres that send signals to the parotid gland to produce saliva and sweat glands. The face and scalp are supplied by sympathetic fibres. After the nerve is damaged, the parasympathetic fibres, which usually help with saliva production, may wrongly reconnect with the sympathetic pathways that go to the sweat glands and blood vessels in the skin. This erroneous connection creates the tell-tale signs of Frey syndrome, such as gustatory sweating (sweating while eating) and facial flushing during chewing.^1,2

Frey syndrome, is a complication after parotid gland surgery, which occurs in about 4% of cases involving benign conditions and up to 20% of cases involving cancer surgery.³ 

Frey syndrome is primarily diagnosed through the symptoms presented by the patient. A minor starch-iodine test can be used for confirmation. During the procedure, the specified affected area of the patient is stained with iodine, then, it dries; after drying, the next step is a starch application or coating as the uppermost layer. For salivation, any specific stimulant is given to the patient.

If, any amount of sweat is found, blue or brown will be observed while the reaction occurs between the iodine and the starch. 62% of the patients who had undergone a parotid gland surgery were positively diagnosed with the test, but only 23% were symptomatic. This demonstrates that Frey syndrome is not uncommon, but is often unnoticed and thus diagnosed.⁴

Surgical methods for preventing Frey syndrome

Increased skin flap thickness

Increasing the skin flap thickness during parotid surgery protects sweat glands from exposure and nerve miscommunication. While early studies suggested thicker flaps reduce Frey syndrome rates, recent research has shown limited impact on incidence but some improvement in severity.

Muscle or fascia flaps

1. Temporoparietal fascia flap (TPFF) 

This flap from the temporal region, effectively reduces the incidence of Frey syndrome, with rates dropping to 4-17%, but it requires a larger incision which increases the chances of potential risks, including nerve injury and increased surgery time.

2. Sternocleidomastoid (SCM) muscle flap

This flap, taken from the neck, can decrease Frey syndrome incidence. Studies show variable results, some indicating reduced rates, but effectiveness can differ based on individual cases.

3. Superficial musculoaponeurotic system (SMAS) flap

This flap acts as a barrier between nerve endings and the skin. Results contradict studies showing its effectiveness in reducing Frey syndrome severity.

Biomaterial and autologous implantation

Acellular dermal matrix (ADM)

ADM, a processed tissue graft, helps create a barrier and shows promise in reducing Frey syndrome.

Abdominal fat grafting 

Fat grafting from the abdomen improves cosmetic outcomes, but limited evidence for reducing Frey syndrome, and can be complicated by issues at the donor site.

These methods vary in effectiveness and risks but aim to prevent or reduce Frey syndrome following parotid surgery.⁴

Surgical treatment for Frey syndrome

Surgery for Frey syndrome is generally a last resort if other treatments don't work. The following are the main options:¹

1. Nerve cutting

This involves cutting nerves like the auriculotemporal or glossopharyngeal nerve. It's a difficult procedure, especially if the area has been previously operated on, and nerves might regrow, reducing effectiveness.

2. Barrier placement

This involves placing materials like acellular dermal matrix (ADM) or fat to create a barrier between the nerves and the skin to prevent sweating.

3. Skin removal

Removing affected skin and covering it with a graft can be done but might leave noticeable scars.

Jacobson’s neurectomy

This procedure cuts the tympanic nerve to help reduce sweating. It helps about 82% of cases but may not completely stop the symptoms as other nerves might still cause sweating.

Additional measures

Removing the chorda tympani nerve and Jacobson’s neurectomy can improve sweating control but might lead to dry mouth and loss of taste. This is usually reserved for severe cases where other treatments have failed.

Complications of Frey syndrome

Frey syndrome does not generally lead to serious health complications, but it can significantly affect a person's quality of life and overall well-being. The discomfort and issues caused by Frey syndrome can extend beyond the immediate postoperative period, sometimes persisting for more than five years after surgery.

Patients might experience reduced social interactions, financial difficulties, trouble speaking, diminished sexual activity, poor nutrition, and an overall lower quality of life. These challenges impact a person’s ability to enjoy life and engage in everyday activities, underscoring the importance of addressing and managing Frey syndrome.¹

Consultations

An effective team approach is essential for managing Frey syndrome and providing the best treatment to improve the quality of life. This team typically includes:

• Otolaryngologists: Specialists of ear, nose, and throat
• Primary care providers: They oversee overall health and coordinate care with specialists
• Nurses: Essential for ongoing patient care, monitoring symptoms, and providing education
• Pharmacists: They play a role in managing and optimising medications that may help alleviate symptoms

Effective management of Frey syndrome involves collaboration among these professionals to cover all aspects of the condition.

Patient education and prevention

Frey syndrome is a minor issue, and its impact on patients might not be much. Many patients report that they are unaware of the potential risk of developing Frey syndrome following parotid surgery. It’s necessary to educate patients preoperatively about the possibility of Frey syndrome to ensure early detection and proper treatment.

If patients feel facial warmth, flushing, or sweating triggered by certain foods after surgery, they should inform their surgeon. The social impact of Frey syndrome can be significant, affecting daily life and comfort, especially in social settings. Early education and prompt treatment are essential to address these issues.

Improving healthcare team outcomes

Managing Frey syndrome effectively involves a collaborative approach. An interlinked professional team of otolaryngologists, plastic surgeons, dermatologists, neurologists, primary care doctors, nurses, pharmacists, and allergists working together.

High-risk patients might benefit from preventive surgical techniques to stop nerve issues, such as those with large parotid tumours or severe trauma. For children with gustatory sweating but no surgical history, primary care providers and allergists should investigate potential food allergies.

Doctors should be alert for symptoms and refer patients to their surgeons if needed because Frey syndrome can develop months or even years after surgery or injury. Collaborative care can include topical antiperspirants, anticholinergics, botulinum toxin injections, or surgery if necessary. Patients should join support groups to manage the social and emotional challenges.

FAQs

How is Frey Syndrome diagnosed? 

Diagnosis is often based on symptoms. A starch-iodine test can confirm the condition by revealing sweat in the affected area on stimulation.

What surgical options are available to prevent Frey Syndrome?

Surgical methods involve increasing flap thickness, using muscle or fascia flaps, and applying biomaterials like acellular dermal matrix or fat grafts.

What are the main surgical treatments for Frey Syndrome?

Surgical treatments are:

• nerve cutting (such as auriculotemporal or glossopharyngeal nerves), 
• placing barriers like ADM or fat, and 
• removing affected skin with grafting.

Are there complications associated with Frey Syndrome surgery? 

Complications are generally minor but can impact quality of life. Issues might include persistent discomfort, reduced social functioning, and financial or nutritional difficulties.

How is Frey Syndrome managed?

Management involves a team approach of otolaryngologists, primary care providers such as nurses, and pharmacists, to ensure comprehensive care and treatment.

Why is patient education important for Frey Syndrome?

Preoperative counselling helps manage risks and expectations, while postoperative education ensures timely reporting of symptoms and effective treatment.

Summary

Frey syndrome, also called auriculotemporal syndrome, is a rare condition that can develop after injury or surgery near the parotid gland. It results from the abnormal reconnection of nerve fibres, resulting in sweating while eating and facial flushing. This syndrome occurs in approximately 4% of cases following benign parotid surgery and up to 20% in cancer-related procedures. Diagnosis is determined by symptoms, with the minor starch-iodine test used to confirm sweating in response to specific stimuli.

Surgery is preferred when other methods do not yield results. Methods include nerve cutting, such as auriculotemporal or glossopharyngeal nerves, and barrier placement using materials like acellular dermal matrix (ADM) or fat. Other options are removing affected skin and Jacobson’s neurectomy, which can help reduce sweating in about 82% of cases but may not fully eliminate symptoms. Despite the available surgical options, Frey syndrome can significantly affect the quality of life, causing long-term discomfort and difficulties in social interactions, communication, and overall well-being.