What causes pain and swelling on the left side of my face?

Unilateral Left Facial Pain and Swelling: Differential Diagnosis and Management

The most critical first step is to rule out life-threatening causes, particularly giant cell arteritis if you are over 50 years old, which requires immediate high-dose corticosteroids to prevent permanent vision loss. 1

Immediate Life-Threatening Causes to Exclude

Giant Cell Arteritis (Temporal Arteritis)

• If you are over 50 years old with facial swelling and pain, giant cell arteritis must be ruled out urgently as it can cause irreversible blindness within days if untreated 1, 2
• Key features include:
  • Jaw claudication (pain with chewing that improves with rest) 1
  • Temporal region pain with scalp tenderness 1
  • Visual disturbances or diplopia 3
  • Systemic symptoms: fever, malaise, myalgia, weight loss 3, 2
  • Physical exam: absent or diminished temporal artery pulse, tender cord-like temporal artery 1, 2
• Immediate laboratory testing required: ESR and C-reactive protein (both markedly elevated) 1
• Treatment must not be delayed: Start minimum 40 mg prednisone daily immediately, even before biopsy 1
• Temporal artery biopsy must be obtained within 2 weeks of starting corticosteroids 1
• Facial swelling is an underrecognized presentation of this condition 2

Cardiac Ischemia

• Left-sided facial pain can rarely represent cardiac ischemia, particularly if pain worsens with physical exertion and resolves with rest 4
• Consider if you have cardiovascular risk factors (hypertension, diabetes, smoking, hyperlipidemia) 4

Common Acute Causes of Unilateral Facial Pain and Swelling

Dental and Oral Infections

• Dental abscess is the most common cause of acute unilateral facial pain with swelling 3
• Pain is typically localized to a specific tooth initially, then spreads 3
• Swelling of the face, particularly the cheek or jaw, indicates spread beyond the tooth 3
• May have visible dental decay, mobile teeth, or gum swelling 3
• Requires urgent dental evaluation and antibiotics 3

Salivary Gland Disorders

• Salivary stones (most common in submandibular gland) cause intermittent pain and swelling that characteristically occurs just before or during eating 3, 5
• The gland becomes tender and swollen 3
• Bimanual palpation may reveal the stone, with slow or absent salivary flow from the duct 3, 1
• Ultrasound is the best initial imaging study 3
• Salivary gland tumors can also cause pain and swelling, particularly if malignant 3
• If you are over 40 with persistent unilateral swelling, induration, or ulceration, malignancy must be excluded with biopsy 5

Maxillary Sinusitis

• Acute sinusitis causes unilateral facial pain and swelling over the cheek 3
• May follow upper respiratory infection or dental procedures on upper premolars/molars 3
• Associated with nasal discharge, nasal congestion, and worsening with bending forward 3
• Dental procedures can create an oral-antral fistula with both oral and nasal discharge 3

Temporomandibular Disorders (TMD)

• TMD is the most common non-dental cause of facial pain, affecting 5-12% of the population 3
• Typically affects ages 20-40 years 3
• Pain in the jaw joint area, often with clicking, locking, or limited jaw opening 3
• Tenderness of muscles of mastication on palpation 3
• May have visible muscle hypertrophy from bruxism (teeth grinding) 3
• Associated with stress, depression, and other chronic pain conditions 3

Neurological Causes (Usually Without Visible Swelling)

Trigeminal Neuralgia

• Characterized by sudden, unilateral, severe, brief stabbing attacks lasting seconds to minutes 3, 6
• Pain is sharp, shooting, electric shock-like, and "frightful" in quality 3
• Triggered by light touch, washing face, cold wind, eating, or brushing teeth 3, 6
• Refractory period between attacks (pain-free intervals) 3
• Does not typically cause visible swelling 3
• MRI is required to exclude tumors, multiple sclerosis, or neurovascular compression 1
• Carbamazepine is the first-line treatment 3, 7

Glossopharyngeal Neuralgia

• Similar sharp, shooting pain but located deep in the ear, back of tongue, tonsils, or neck 3
• Triggered by swallowing, coughing, or touching the ear 3
• Can rarely provoke syncope 3, 1

Critical Diagnostic Approach

History Elements to Obtain

• Temporal pattern: continuous vs. episodic, duration of attacks 3, 8
• Pain quality: sharp/shooting vs. dull/aching vs. burning 3, 8
• Triggers: chewing, touch, temperature changes, eating, physical exertion 3, 8
• Associated symptoms: fever, visual changes, nasal discharge, jaw clicking, systemic symptoms 3
• Age and risk factors: age >50, cardiovascular risk factors, recent dental work 1, 2

Physical Examination Priorities

• Palpate temporal arteries bilaterally for tenderness, nodularity, or absent pulse 1
• Examine teeth and oral mucosa with good lighting for decay, mobile teeth, gum swelling, or lesions 3
• Bimanual palpation of salivary glands (submandibular and parotid) for stones or masses 3, 1
• Palpate muscles of mastication for tenderness and trigger points 3
• Test jaw range of motion for clicking, locking, or limitation 3
• Light touch testing in all three trigeminal divisions to identify trigger zones or sensory deficits 1
• Palpate for cervical lymphadenopathy which may indicate infection or malignancy 5

Imaging and Laboratory Studies

• If age >50 with jaw pain or systemic symptoms: immediate ESR and CRP 1
• Dental X-rays or panoramic tomography for suspected dental causes 3
• Ultrasound for salivary gland disorders 3
• MRI with contrast for suspected neurological causes, tumors, or when diagnosis unclear 1, 9
• CT scan is the mainstay for acute facial swelling in emergency settings 9

Red Flags Requiring Urgent Specialist Referral

• Age >50 with new-onset facial pain, jaw claudication, or visual symptoms → immediate evaluation for giant cell arteritis 1, 2
• Pain associated with physical exertion that resolves with rest → cardiac evaluation 4
• Progressive neurological symptoms or sensory deficits → neurology referral 8
• Unilateral swelling with induration, ulceration, or non-healing lesions in patients >40 → biopsy to exclude malignancy 5
• Severe dental infection with facial swelling → urgent dental or oral surgery referral 3
• Salivary gland stones or masses → oral/maxillofacial surgery referral 3, 1

Common Pitfalls to Avoid

• Do not dismiss facial pain in patients over 50 as TMD without excluding giant cell arteritis 1, 2
• Do not perform surgical procedures for facial pain without objective findings 8
• Do not delay corticosteroids while awaiting temporal artery biopsy if giant cell arteritis is suspected 1
• Do not assume all unilateral facial pain is dental—consider cardiac ischemia if associated with exertion 4
• Do not miss the 42% of trigeminal neuralgia patients who also have atypical facial pain requiring separate treatment 10