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 Table of Contents  
Year : 2021  |  Volume : 33  |  Issue : 4  |  Page : 484-486

Frey's syndrome: A misdirected reflex action!! – A case report

1 Department of Oral Medicine and Radiology, SRM Dental College, Chennai, Tamil Nadu, India
2 Department of Oral Medicine and Radiology, Madha Dental College and Hospital, Chennai, Tamil Nadu, India

Date of Submission23-Jul-2021
Date of Decision11-Oct-2021
Date of Acceptance27-Oct-2021
Date of Web Publication27-Dec-2021

Correspondence Address:
Dr. Anuradha Ganesan
Department of Oral Medicine and Radiology, SRM Dental College, Ramapuram, Chennai - 89, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jiaomr.jiaomr_207_21

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The incidence of Frey's syndrome after parotidectomy greatly varies in the literature. It is a sequelae of any surgery near the pretragal region like parotidectomy or condylar surgeries which might cause embarrassment and considerable social discomfort and may further result in disruptions and disturbances in daily life. Hence, frequent follow-ups after the surgeries, early diagnosis, and proper management of Frey's syndrome may help to alleviate symptoms and improve quality of life for the patient. This case report highlights a case of Frey's syndrome followed by the surgical management of condylar fracture and also highlights the management of the syndrome.

Keywords: Frey's syndrome, gustatory sweating, minor starch test, parotidectomy

How to cite this article:
Ganesan A, Rao BE. Frey's syndrome: A misdirected reflex action!! – A case report. J Indian Acad Oral Med Radiol 2021;33:484-6

How to cite this URL:
Ganesan A, Rao BE. Frey's syndrome: A misdirected reflex action!! – A case report. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2022 Aug 8];33:484-6. Available from: https://www.jiaomr.in/text.asp?2021/33/4/484/333867

   Introduction Top

Frey's syndrome is a very rare disorder first described in 1757 and then in 1853 (Dr. Jules Baillarger) and 1897 (Weber) following parotid gland abscess drainage. In 1923 Lucie Frey mentioned and gave a detailed assessment of this syndrome which occurs after direct damage to auriculotemporal nerve and coined the term auriculotemporal syndrome.[1],[2]

The main symptom of Frey's syndrome is undesirable sweating and flushing occurring on the cheek, temple (temporal region) or behind the ears (retro-auricular region) after eating certain foods, especially those with a strong salivary response.[3]

   Case Report Top

Clinical history

A 42-year-old male patient had visited our dental clinic with a chief complaint of discomfort and unusual sweating on the right side of the face during eating for the past six months. Patient gave a history of road traffic accident before 3 years and had a fracture in his lower jaw, following which surgery was performed on both right and left side. The previous reports showed there was a bicondylar fracture and open reduction and internal fixation of the right and left condyle with a preauricular approach. For the past 6 months, the patient has developed sweating over the temporal regions during intake of spicy and sour food.

Extraoral examination revealed presence of linear scars bilaterally in the pretragal region and also in the chin region [Figure 1]. Intraorally there was Ellis class III fracture in upper right and left central incisor and left lateral incisor. Orthopantomograph (OPG) showed presence of microplates in the left and right condyle and also periapical changes in the upper right and left central incisor [Figure 1].
Figure 1: Reveals sweat spots in right and left temporal region & OPG showing presence of mini plates

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Diagnostic assessment

On correlation with history and clinical examination, the case was provisionally diagnosed as Frey's syndrome and was confirmed by performing Minor- starch iodine test. The affected area was coated with 1% iodine solution and was allowed to dry. The starch power was applied over the skin and patient was given a tablet of Vitamin C 500 mg as a salivary stimulant. Subsequently after taking the tablet, the bluish-black color was noted over the right-side temple region which suggested a positive starch iodine test [Figure 2].
Figure 2: Shows positive minor iodine starch test

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Therapeutic intervention

Patient opted for conservative follow-up protocol rather than any interventional therapy. He was referred to a dermatologist and patient received 30 units of botulinum toxin A (2.5 U/0.1 ml, 3 U/cm2) intracutaneously in the affected site. Patient was asymptomatic after 7 days and is on regular follow-up.

Follow- up and outcome

At the follow-up after 2 and 6 months patient continued to be asymptomatic and the minor starch iodine test was negative. No side effects or complications such as muscle paresis or paralysis, hyperesthesia or pain, hematoma were experienced by the patient immediately or following treatment sessions or at a later time. [Figure 3] and [Table 1]
Figure 3: Post treatment follow-up

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Table 1: Timeline of events in this case

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   Discussion Top

Frey's syndrome is a postoperative complication of parotid gland surgeries, manifested as sweating and/or dermal flushing, during salivary stimulation and the clinical incidence of the syndrome after parotid surgery is reported to be as high as 53%.[3] The authors mentioned that the damage to the nerve may cause destruction of sympathetic fibers leading to parasympathetic hypersensitivity and stimulation. The more acceptable theory is aberrant regeneration, which is based on nerve regeneration and the misdirection of regenerating parasympathetic fibers to the denervated sweat glands resulting in simultaneous activation of parotid and sweat glands. Regeneration of postganglionic parasympathetic nerve fibers in the skin takes a certain amount of time, suggesting a latent period between interoperative nerve injury and onset of Frey' syndrome. Also, the skin area exhibiting gustatory sweating can progress and gradually increase in size according to the different lengths of time required by nerve fibers regenerating to reach effector organ at ranging distances from the proximal nerve endings.[4],[5] The symptoms of Frey's syndrome can include flushing sweating, burning, neuralgia and itching. On mastication, it immediately manifests as hemifacial flushing and sweating on the cheeks, temporal and retro auricular region that increase salivation.[6] Diagnosis is mainly on the clinical history, but confirmatory testing can be done with minor starch iodine test. Minor described very simple test in 1927 which was to apply an iodine solution on the skin around the preauricular area (aqueous antiseptic solution containing 10% poly vinyl-pyrrolidone). The solution was applied evenly on the skin and allowed to dry. The area was covered by a layer of starch base (corn starch, flour) followed by gustatory stimulation. The starch turns blue/brown in the presence of iodine and sweat and in a positive Minor iodine starch test.[7] Other than the minors test thermography can also be used to detect Frey's syndrome at the earliest.[8]

Differential diagnosis can be an allergy, especially food allergy in which symptoms are localized to the parotid region, and absence of other atopic symptoms. In general, hyperhidrosis can be primary or secondary. Primary is usually present with at least 6 months of excessive symmetrical and bilateral sweating, age younger than 25 years, positive family history, and cessation of sweating during sleep. Secondary hyperhidrosis can be induced by drugs, toxins, thyroid dysfunction, pituitary dysfunction, metabolic disorders, malignancy, central nerve disorders, or congenital disorders (such as Riley–Day syndrome). Emotional sweating is activated by emotional stimuli and does not occur when the patient is sleeping or sedated.

There are various forms of treatment for Frey syndrome, both non-invasive and invasive which have varying degrees of success. Topical anticholinergics like Scopolamine and glycopyrrolate easily penetrates the skin and blocks cholinergic transmission. Rather than these topical medications topical anti-perspirants (deodorant) reduce sweating, astringents like ammonium alum shrinks the skin and plugs the pores and topical α agonist (clonidine) can be used. In the present case, as the patient opted for conservative therapy, botulinum toxin injection was used. Currently, Botulinum Toxin A (BTA) is the most widely used agent for intradermal injection. Previous studies have demonstrated that patients undergoing BTA injection demonstrate improvement in symptoms of gustatory sweating and flushing.[9] The results and patient comfort achieved in this case were consistent with previously published reports using BTA. In addition, it has been shown to improve patient quality of life. Injection of alcohol to the otic ganglion has been proposed and tried in some cases. Botulinum toxin A injections are minimally invasive but it is effective in most of the patients, well-tolerated and can be easily repeated when required. The most common surgical method is the re-elevation of cheek skin flap and interposition of various tissue barriers between the cheek skin and the parotid gland.[10]

   Conclusion Top

Frey's syndrome has distinguishing features that makes it unique from other conditions, but in few circumstances, it becomes a tedious job for the oral physicians to make out the timely diagnosis. Hence, an early diagnosis and proper follow-ups after the surgeries involving the pretragal regions is necessary to avoid future complications.

Key Messages: Frey's syndrome is a relatively rare presentation, the diagnosis of which is instrumental in providing successful therapy. This syndrome occurs after direct damage to auriculotemporal nerve and is also called auriculotemporal syndrome. An early diagnosis and proper follow-up after the surgeries involving the pretragal regions is necessary to avoid future complications.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Dulguerov P, Marchal F, Gysin C. Frey syndrome before Frey: The correct history. Laryngoscope 1999;109:1471-3.  Back to cited text no. 1
Motz KM, Kim YJ. Auriculotemporal syndrome (Frey syndrome). Otolaryngol Clin North Am 2016;49:501-9.  Back to cited text no. 2
Dulguerov P, Quinodoz D, Cosendai G, Piletta P, Marchal F, Lehmann W. Prevention of Frey syndrome during parotidectomy. Arch Otolaryngol Head Neck Surg 1999;125:833-9.  Back to cited text no. 3
Sverzut CE, Trivellato AE, Serra EC, Ferraz EP, Sverzut AT. Frey's syndrome after condylar fracture: Case report. Braz Dent J 2004;15:159-62.  Back to cited text no. 4
Malatskey S, Rabinovich I, Fradis M, Peled M. Frey syndrome--delayed clinical onset: A case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:338-40.  Back to cited text no. 5
Izikson L, English JC III, Zirwas MJ. The flushing patient: Differential diagnosis, workup, and treatment. J Am Acad Dermatol 2006;55:193-208.  Back to cited text no. 6
Minor V. Einneues Verfahrenzu der klinischen Untersuchung der Schweissabsonderung. Dtsch Z Nervenheilkd 1928;101:302-8.  Back to cited text no. 7
Green RJ, Endersby S, Allen J, Adams J. Role of medical thermography in treatment of Frey's syndrome with botulinum toxin A. Br J Oral Maxillofac Surg 2014;52:90-2.  Back to cited text no. 8
Beerens A, Snow G. Botulinum toxin A in the treatment of patients with Frey syndrome. Br J Surg 2002;89:116-9.  Back to cited text no. 9
Blanc S, Bourrier T, Boralevi F, Sabouraud-Leclerc D, Pham-Thi N, Couderc L, et al. Frey Syndrome Collaborators. Frey syndrome. J Pediatr 2016;174:211-7.e2.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]


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