Blepharitis and Meibomian Gland Dysfunction

Blepharitis & MGD: Overview - Lid Edge Lowdown

• Blepharitis: Chronic inflammation of eyelid margins.
  • Anterior: Involves skin, eyelashes; often Staphylococcal or seborrhoeic.
  • Posterior: Involves Meibomian gland orifices; linked to MGD.
• Meibomian Gland Dysfunction (MGD): Altered Meibomian gland secretion/obstruction, leading to tear film instability.
  • Key cause of evaporative dry eye.

⭐ Posterior blepharitis is nearly synonymous with Meibomian Gland Dysfunction (MGD).

Anterior Blepharitis - Frontline Inflammation

• Inflammation at eyelash base. Two main types:
  • Staphylococcal:
    • Hard scales, collarettes (fibrin crusts around lash base).
    • Madarosis (lash loss), trichiasis (misdirected lashes), recurrent hordeolum.
    • Often younger patients; more symptomatic.
  • Seborrheic:
    • Greasy, soft scales on lashes & lid margin; foamy tears.
    • Less inflammation; associated with seborrheic dermatitis (scalp/face).
    • Lashes often matted.

⭐ Collarettes are pathognomonic for Staphylococcal anterior blepharitis.

Posterior Blepharitis & MGD - Gland Gridlock

• Central: Meibomian Gland Dysfunction (MGD).
• Pathophysiology:
  • Altered meibum: ↑viscosity, ↑melting point.
  • Bacterial lipases → inflammatory free fatty acids.
  • Results in: Gland obstruction, inspissation, dilation.
• Key Signs:
  • Lid margin: Telangiectasias, hyperemia.
  • Glands: Capped/pouting orifices; thick, "toothpaste" secretions; gland dropout.
  • Tear film: ↓TBUT, frothy.
• Symptoms: Burning, foreign body sensation (FBS), blurred vision.
• Associated with: Acne rosacea.

⭐ MGD is the most common cause of evaporative dry eye disease.

Blepharitis: Complications - Lid's Angry Aftermath

• Lid Margin:
  • Madarosis (loss of lashes)
  • Trichiasis (misdirected lashes)
  • Poliosis (white lashes)
  • Tylosis (lid margin thickening)
  • Lid ulceration, scarring
• Glandular:
  • Hordeolum (stye) - acute
  • Chalazion - chronic granuloma
• Conjunctival/Corneal:
  • Chronic conjunctivitis
  • Dry eye syndrome (secondary to MGD)
  • Marginal keratitis (sterile infiltrates)
  • Phlyctenular keratoconjunctivitis
  • Corneal neovascularization, pannus

⭐ Recurrent chalazia, especially in the same location, warrant biopsy to rule out sebaceous gland carcinoma.

• Tear Film Instability: Common due to altered meibum quality/quantity in MGD.
• Contact Lens Intolerance

Blepharitis: Dx & Management - Clearing the View

• Dx (Clinical):
  • Anterior: Lid margin redness, scurf, collarettes.
  • Posterior (MGD): Inspissated glands, frothy tears, telangiectasia.
• Management:
  • Core: Lid hygiene (warm compresses, scrubs).
  • Medical: Topical antibiotics (e.g., azithromycin), oral tetracyclines (MGD), short-course steroids. Artificial tears.

⭐ Chronic blepharitis can lead to madarosis (loss of eyelashes).

High‑Yield Points - ⚡ Biggest Takeaways

• Blepharitis is chronic eyelid margin inflammation. Anterior involves lash base (Staphylococcal, Seborrheic); Posterior is Meibomian Gland Dysfunction (MGD).
• Staphylococcal blepharitis: Hard, collarette scales, madarosis, trichiasis. Seborrheic type: Greasy scales.
• MGD: Blocked meibomian glands cause inspissated secretions, frothy tears, lid margin telangiectasia; linked with rosacea.
• Cornerstone of all types: Lid hygiene (warm compresses, lid scrubs).
• Medical treatment: Topical antibiotics for anterior; oral doxycycline for MGD.
• Complications: Recurrent chalazia/hordeola, dry eye syndrome, marginal keratitis.