What are the causes of an eye stye (hordeolum)?

Causes of Eye Stye (Hordeolum)

An eye stye (hordeolum) is caused by bacterial infection of the eyelid's oil glands, most commonly by Staphylococcus aureus, with the infection affecting either the meibomian glands internally or the glands of Zeis/Moll externally. 1, 2, 3

Primary Causative Mechanism

The fundamental cause is bacterial infection of obstructed sebaceous glands in the eyelid margin 1, 3:

• Internal hordeolum: Infection of the meibomian glands within the tarsal plate 3
• External hordeolum (stye): Infection of the glands of Zeis or Moll associated with eyelash follicles 4, 3
• Staphylococcus aureus is the predominant pathogen responsible for these infections 2

Major Predisposing Factors

Eyelid Conditions

• Bacterial blepharitis is the most common predisposing factor and frequently coexists with hordeolum 1, 5
• Meibomian gland dysfunction contributes to gland obstruction and subsequent infection 1, 5
• Chronic inflammation of the eyelid margin creates an environment conducive to bacterial overgrowth 1

Systemic and Dermatologic Conditions

• Rosacea predisposes to hordeolum development and is associated with childhood stye history 1
• Seborrheic dermatitis increases risk through chronic eyelid inflammation 5
• Components of metabolic syndrome are associated with higher risk for blepharitis, which then predisposes to hordeolum 1

Medication-Related Causes

• Isotretinoin use may increase risk of hordeolum 1
• Dupilumab therapy has been associated with increased hordeolum risk 1

Contact Lens-Related Factors

• Contact lens wear, particularly with giant papillary conjunctivitis, may increase hordeolum risk 1
• This parallels the well-established risk of contact lens wear for bacterial keratitis, especially with overnight wear and poor hygiene 6

Pathophysiologic Sequence

The infection develops through this mechanism 4, 3:

1. Obstruction of the sebaceous gland orifice occurs (from debris, inflammation, or gland dysfunction)
2. Bacterial colonization of the obstructed gland, predominantly by Staphylococcus aureus 2
3. Acute purulent inflammation develops with rapid onset 1
4. Tissue damage results from both bacterial toxins (alpha-toxin, beta-toxin, gamma-toxin, leukocidins) and the inflammatory response 2

Important Clinical Distinctions

Do not confuse hordeolum with chalazion, as they have different causes 1, 5, 3:

• Hordeolum: Acute bacterial infection with rapid onset, painful, purulent 1
• Chalazion: Chronic lipogranulomatous inflammation from gland obstruction without acute infection, gradual onset, typically painless 5, 3

Common Pitfall

The most critical error is missing underlying chronic blepharitis that predisposes to recurrent hordeola 1. Failure to address this underlying condition leads to repeated infections despite treating individual styes.