Differential Diagnosis of Bilateral Facial Burning

Primary Differential Diagnoses

• Bilateral facial burning is most commonly caused by burning mouth syndrome (BMS) in peri- and post-menopausal women, bilateral temporomandibular disorders (TMD), or post-traumatic trigeminal neuropathic pain, with critical red flags including giant cell arteritis in patients over 50 years and progressive cancer-related neuropathic pain 1, 2, 3
• The British Journal of Anaesthesia recommends that burning mouth syndrome (BMS) is the most likely diagnosis for bilateral continuous burning, particularly affecting the tongue tip, lateral borders, lips, palate, and buccal mucosa 2, 3, 4
• BMS predominantly affects peri- and post-menopausal women with normal-appearing oral mucosa on examination 2, 3
• Associated features of BMS include dry mouth, abnormal taste, depression, and poor quality of life 2, 3, 4
• The British Journal of Anaesthesia states that pain severity in BMS ranges from mild to severe, with continuous timing in most instances 2, 3
• Eating may aggravate symptoms in some BMS patients while relieving them in others 2, 3
• The British Journal of Anaesthesia recommends that bilateral temporomandibular disorders (TMD) is the second most common cause of bilateral facial pain, involving muscles of mastication 1, 5, 6
• TMD pain is musculoskeletal in nature and may be associated with other chronic pain conditions 1, 5, 6
• The British Journal of Anaesthesia notes that TMD typically presents without the burning quality characteristic of neuropathic pain 1
• Post-traumatic trigeminal neuropathic pain can present bilaterally if trauma affected both sides of the face 2, 3, 7
• This condition is characterized by continuous burning, tingling pain within 3-6 months of trauma 2, 3
• A history of dental procedures or facial trauma is key in diagnosing post-traumatic trigeminal neuropathic pain 2, 3
• The British Journal of Anaesthesia recommends that patients with post-traumatic trigeminal neuropathic pain may have allodynia or other sensory changes on examination 2, 3

Secondary Causes to Exclude

• The British Journal of Anaesthesia states that oral candidiasis, mucosal lesions requiring direct visualization and testing should be excluded as secondary causes 2, 3, 4
• Poor oral hygiene or irritating oral care products containing alcohol should also be excluded 4
• Hematological disorders (anemia, vitamin B12 deficiency) requiring laboratory evaluation should be excluded as secondary causes 2, 3, 4
• Autoimmune disorders (Sjögren's syndrome, lupus) should also be excluded 2, 3, 4
• Pharmacological side effects from medications should be considered as secondary causes 2, 3, 4

Critical Red Flags Requiring Urgent Evaluation

• The British Journal of Anaesthesia recommends that giant cell arteritis must be distinguished from TMD, especially in patients over 50 years old 1, 5, 8
• Giant cell arteritis presents with temporal artery tenderness, jaw claudication, visual symptoms, and elevated inflammatory markers 1, 5
• Cancer can present as progressive neuropathic pain with burning quality 1, 5, 8
• The British Journal of Anaesthesia states that an MRI of brain and trigeminal nerve is mandatory to exclude structural lesions, tumors, or nerve compression 7

Diagnostic Approach

• The British Journal of Anaesthesia recommends that essential history elements include timing, quality, aggravating factors, associated symptoms, and trauma history 2, 3, 6, 8
• Physical examination findings should include inspection of oral mucosa, testing for allodynia, palpation of temporomandibular joints and muscles of mastication, and qualitative sensory testing 1, 2, 3, 6, 7
• Laboratory investigations should include complete blood count, vitamin B12, folate, glucose, thyroid function, and inflammatory markers (ESR/CRP if over 50 years) 4, 7
• Microbial testing, such as oral swab for candidiasis, should be performed if mucosal changes are present 4
• Imaging, such as MRI of brain and trigeminal nerve, is mandatory to exclude structural lesions, tumors, or nerve compression 7

Management Algorithm

• The British Journal of Anaesthesia recommends that first-line treatment for BMS includes reassurance, patient education, and cognitive behavioral therapy 2, 3, 4
• Pharmacological treatment for BMS includes gabapentin, with a recommended dose of 300mg at bedtime, titrating to 900-3600mg daily in divided doses 4, 7
• Alternative agents for BMS include amitriptyline, alpha lipoic acid combined with gabapentin, or topical clonazepam 4
• Symptomatic management for BMS includes saliva substitutes for dry mouth, avoiding irritating oral products, and bland oral rinses for taste disturbances 4
• The British Journal of Anaesthesia recommends that early diagnosis with reassurance and simple physiotherapy is essential for patients with TMD and good coping strategies 1, 5, 6
• Night splints fabricated by dentists are recommended for TMD patients 1, 5
• Neuropathic pain medications following standard guidelines are recommended for post-traumatic trigeminal neuropathic pain 2, 3, 7
• Gabapentin is recommended as the first-line agent for post-traumatic trigeminal neuropathic pain, with the same dosing as BMS 7
• Cognitive behavioral therapy should be initiated early for post-traumatic trigeminal neuropathic pain 7

Common Pitfalls to Avoid

• Failing to exclude secondary causes before diagnosing primary BMS can lead to missed treatable conditions 2, 3, 4
• Inadequate reassurance about BMS prognosis can increase patient anxiety and worsen quality of life 2, 3, 4
• Missing giant cell arteritis in patients over 50 years can result in permanent vision loss 1, 5, 8
• Performing invasive procedures without objective findings or when pain is the only symptom should be avoided 8
• Treatment failures are common in BMS management, and patients should be informed about the chronic nature and referred to pain specialists or neurologists if inadequate response after 4-6 weeks [4, @