What is the diagnostic approach for blepharitis?

Diagnostic Approach for Blepharitis

Blepharitis is diagnosed primarily through clinical evaluation combining a focused patient history and slit-lamp biomicroscopic examination of the eyelids, with ancillary testing reserved for specific scenarios such as treatment failure or suspected Demodex infestation. 1

Clinical History

The diagnostic evaluation begins with targeted questioning about specific symptom patterns and associated conditions:

Symptom Assessment

• Key symptoms to elicit: redness, irritation, burning, tearing, itching, crusting of eyelashes, eyelash loss, eyelid sticking, blurred or fluctuating vision, contact lens intolerance, photophobia, increased blinking frequency, and recurrent hordeola 1
• Timing pattern is diagnostically important: symptoms worse in the morning suggest blepharitis, whereas symptoms worsening later in the day indicate aqueous deficient dry eye 1
• Duration and laterality: document whether symptoms are unilateral or bilateral and how long they have persisted 1

Exacerbating Factors and Associations

• Environmental and lifestyle triggers: smoke, allergens, wind, contact lenses, low humidity, retinoids, diet, alcohol consumption, and eye makeup 1
• Systemic disease associations: specifically inquire about rosacea, atopy, psoriasis, and graft-versus-host disease 1
• Medication history: antihistamines, anticholinergic drugs, isotretinoin, and dupilumab can cause or worsen blepharitis 1, 2
• Surgical history: previous blepharoplasty increases tear evaporation; history of hordeola/chalazia is common in posterior blepharitis 1

Physical Examination

External Examination (Well-Lighted Room)

Skin evaluation:

• Look for rosacea features including rhinophyma, erythema, telangiectasia, papules, pustules, and hypertrophic sebaceous glands in malar areas 1

Eyelid assessment:

• Abnormal positioning (ectropion, entropion), lagophthalmos, blink response, and eyelid laxity 1
• Eyelash abnormalities: loss, breakage, or misdirection 1
• Eyelid margin vascularization or hyperemia 1
• Abnormal deposits or sleeves at the eyelash base 1
• Ulceration, vesicles, scaling, hyperkeratosis 1
• Chalazion or hordeolum presence 1
• Scarring 1

Slit-Lamp Biomicroscopy

Tear film evaluation:

• Tear meniscus height 1
• Tear film break-up time and pattern 1
• Foamy discharge on eyelid margin 1
• Debris in tear film 1

Posterior eyelid margin (critical for MGD diagnosis):

• Meibomian orifice abnormalities: capping, pouting, retroplacement, metaplasia, obliteration 1
• Meibomian secretion characteristics: expressibility, thickness, turbidity, color 1
• Vascularization, keratinization, nodularity, thickening, scarring/fibrosis 1

Tarsal conjunctiva (evert eyelids):

• Meibomian gland and duct appearance: dilation and inflammation 1

Bulbar conjunctiva:

• Hyperemia, phlyctenules, follicles, conjunctival chalasis 1
• Punctate staining with fluorescein (cornea) or rose bengal/lissamine green (conjunctiva) 1

Corneal examination:

• Epithelial defects, punctate staining 1
• Edema, infiltrates, ulcers, scars (typically small subepithelial or superficial stromal, circumferential, midperipheral with clear zone from limbus) 1
• Vascularization, scarring, pannus, phlyctenules 1

Ancillary Diagnostic Testing

Microbiologic cultures:

• Indicated for recurrent anterior blepharitis with severe inflammation or treatment failure 1, 2

Demodex evaluation:

• Epilate eyelashes and examine microscopically by placing on glass slide with fluorescein drop and coverslip 1, 2
• Can also examine using slit lamp with 90-diopter condensing lens 1
• Suspect Demodex when lash collarettes persist despite treatment 1

Meibomian gland assessment:

• Apply pressure to lower eyelids with fingers or cotton-tipped applicator to assess gland expression 1, 2
• Interferometry technology can evaluate lipid-layer thickness and correlates with dry eye symptoms 1

Critical Diagnostic Pitfalls

Consider malignancy when:

• Chronic blepharitis is unresponsive to therapy, especially with unilateral involvement 1, 2
• Marked asymmetry, resistance to therapy, or unifocal recurrent chalazia occur 1, 2
• Loss of normal eyelid margin anatomy or focal lash loss (ciliary madarosis) is present 1
• Eyelid biopsy is indicated in these scenarios 1, 2
• Consult pathology before biopsy for suspected sebaceous carcinoma to discuss frozen sections and conjunctival mapping for pagetoid spread 1

Evaluate for ocular mucous membrane pemphigoid:

• Perform complete ocular surface examination in chronic blepharitis unresponsive to standard treatment 1
• Look for conjunctival cicatricial changes, forniceal foreshortening, or symblepharon formation 1
• If cicatrizing disease is present, initiate workup including immunofluorescence studies of biopsy specimen 1

Pediatric considerations:

• Blepharokeratoconjunctivitis is often unrecognized in children and can be more severe, potentially causing amblyopia 2
• Children have higher incidence of corneal ulceration and perforation complications 1