What are the possible causes of a unilateral burning sensation of the upper eyelid?

Unilateral Upper Eyelid Burning Sensation: Causes

A unilateral burning sensation of the upper eyelid is most commonly caused by blepharitis (anterior or posterior), followed by neuropathic ocular pain, dry eye disease, or less commonly, neurogenic causes including post-viral neuropathy or isolated nerve dysfunction.

Primary Differential Diagnoses

1. Blepharitis (Most Common)

Blepharitis is a chronic inflammatory condition affecting the eyelid margin and represents one of the most frequent causes of eyelid irritation and burning 1. Key features include:

• Anterior blepharitis: Affects eyelid skin, lash base, and follicles with staphylococcal or seborrheic etiology
• Posterior blepharitis: Involves meibomian gland dysfunction (MGD) with terminal duct obstruction
• Classic symptoms: Burning sensation, irritation, tearing, photophobia, and redness 2
• Clinical signs to look for: Eyelid margin erythema, collarette formation at lash base, scaling, crusting, telangiectatic vessels, inspissated meibomian glands 1, 2

Unilateral presentation is possible, though bilateral involvement is more typical. The chronic nature and overlap of symptoms across subtypes make this a primary consideration 1.

2. Neuropathic Ocular Pain (NOP)

This represents dysfunction of peripheral or central nerves in the trigeminal pathway (V1 distribution) 3. Critical diagnostic features:

• Characteristic pain quality: Burning, stinging, or aching sensation that is disproportionate to clinical findings
• Associated symptoms: Photophobia, wind hyperalgesia, sensitivity to light touch
• Key diagnostic clue: Symptoms outweigh observed signs of disease 3
• Diagnostic test: Anesthetic challenge test—if topical anesthetic improves pain, suggests peripheral neuropathic or nociceptive component; if no improvement, suggests central or non-ocular cause 3

This subset of "burning eye syndrome" may develop post-surgically, post-infection, from chronic ocular surface abnormalities, or idiopathically 4. The burning quality specifically aligns with neuropathic mechanisms involving peripheral and central sensitization 4.

3. Neurogenic Dry Eye Disease

Isolated parasympathetic denervation of the lacrimal gland can present with unilateral symptoms 5:

• Presentation: Pain and burning sensation in affected eye with markedly reduced tear production
• Diagnostic finding: Dramatically asymmetric Schirmer test values (e.g., 24 mm vs 1 mm between eyes)
• Associated feature: May have ipsilateral dry nasal cavity 5
• Most common etiology: Idiopathic, followed by trauma 5

4. Post-Viral Neuropathy

Emerging recognition of cranial nerve involvement following viral infections, particularly COVID-19 6:

• Presentation: Unilateral paresthesia, dysesthesia, or burning in infraorbital/periorbital distribution
• Timing: Develops following upper respiratory or systemic viral illness
• Diagnostic approach: Exclusion of structural causes (imaging, endoscopy), nerve block for localization 6

Diagnostic Algorithm

Step 1: Examine the eyelid margin and ocular surface

• Look for signs of blepharitis: erythema, scaling, collarettes, meibomian gland abnormalities 1
• Assess tear film: Schirmer test, tear break-up time, fluorescein staining 3

Step 2: Assess symptom-to-sign ratio

• If burning sensation is disproportionate to clinical findings → consider NOP 3
• Perform anesthetic challenge test if NOP suspected 3

Step 3: Check for neurologic involvement

• Assess lacrimal function bilaterally (Schirmer test)
• If marked asymmetry with minimal ocular surface disease → consider neurogenic dry eye 5
• Obtain history of recent viral illness, trauma, or surgery 5, 6

Step 4: Rule out rare causes

• Imaging if concern for orbital/sinus pathology, neoplasm, or inflammatory disease 7
• Consider autoimmune workup if other systemic features present 5

Common Pitfalls to Avoid

• Don't assume bilateral disease: While blepharitis is often bilateral, unilateral presentations occur and should not exclude this diagnosis 1, 2
• Don't dismiss symptoms exceeding signs: This is the hallmark of neuropathic pain, not psychosomatic disease 3, 4
• Don't overlook recent infections: Post-viral neuropathies are increasingly recognized and may occur without confirmatory testing 6
• Don't forget the nasal cavity: Ipsilateral nasal dryness suggests parasympathetic denervation affecting both lacrimal and nasal glands 5

Treatment Considerations by Etiology

For blepharitis: Long-term eyelid hygiene is essential; topical antibiotics or anti-inflammatories for acute exacerbations 1

For NOP with peripheral component: Autologous serum tears, nerve regenerative therapies 3

For NOP with central component: Oral neuromodulators (gabapentin, pregabalin, duloxetine, amitriptyline) requiring 3-4 months at therapeutic dose 3

For neurogenic dry eye: Lubricants as first-line; pilocarpine therapy has shown efficacy in animal models but requires further human study 5