Blepharitis

Definition

Blepharitis is a common chronic inflammation of the eyelid margins, often associated with bacterial colonization, seborrheic dermatitis, or meibomian gland dysfunction, causing eyelid irritation and ocular surface discomfort.

Epidemiology

• Common in adults; prevalence increases with age
• Affects both genders equally
• Often associated with seborrheic dermatitis, rosacea, or dry eye syndrome
• Chronic and recurrent in nature
• Can occur at any age, including children, especially with skin conditions

Etiology

• Anterior blepharitis: bacterial (Staphylococcus aureus), seborrheic dermatitis
• Posterior blepharitis: meibomian gland dysfunction, rosacea
• Mixed forms are common
• Allergic reactions or environmental irritants
• Associated systemic conditions: seborrheic dermatitis, rosacea, eczema

Pathophysiology

• Inflammation of eyelid margin leads to erythema, scaling, and irritation
• Bacterial colonization produces exotoxins causing eyelid and ocular surface inflammation
• Meibomian gland dysfunction results in altered lipid secretion, tear film instability, and evaporative dry eye
• Chronic inflammation may lead to eyelash abnormalities, eyelid thickening, and keratitis
• Tear film disruption exacerbates ocular surface irritation and discomfort