What Causes a Hordeolum (Stye)?
A hordeolum is caused by bacterial infection of the eyelid oil glands, most commonly by Staphylococcus species. 1
Pathophysiology
A hordeolum results from bacterial infection affecting the oil-producing glands of the eyelid margin 2, 3, 4:
- Internal hordeolum: Infection of the meibomian glands (deep sebaceous glands within the tarsal plate) 5
- External hordeolum (stye): Infection of the glands of Zeis or Moll, typically associated with eyelash follicle obstruction 5
The infection causes acute purulent localized swelling and inflammation of the eyelid 5.
Primary Causative Organisms
Staphylococcal species are the predominant bacterial pathogens 1:
- Coagulase-negative Staphylococcus (most common, accounting for 68.4% of related ocular infections) 1
- Staphylococcus aureus (6.8% of related infections) 1
- Streptococcus species (8.2% of related infections) 1
These are the same organisms commonly found on the ocular surface and associated with blepharitis 1.
Risk Factors and Associated Conditions
Several conditions predispose to hordeolum development 1:
- Chronic blepharitis (eyelid margin inflammation) - creates an environment conducive to bacterial overgrowth 1
- Meibomian gland dysfunction (MGD) - obstruction of oil glands provides a nidus for infection 1
- Rosacea - associated with recurrent chalazia and hordeola, particularly in children 1
- Seborrheic dermatitis - contributes to eyelid margin disease 1
- Demodex mite infestation - may play a role in pathogenesis 1
Pediatric Considerations
Children with a history of styes have increased risk of developing adult rosacea 1. In children, recurrent hordeola should prompt evaluation for:
- Chronic blepharokeratoconjunctivitis (often unrecognized and more severe in children) 1
- Underlying rosacea (facial signs may be subtle) 1
- Associated atopy 1
Medication-Related Causes
Certain medications increase hordeolum risk 1:
- Isotretinoin (for severe acne) - significantly increases S. aureus colonization and causes blepharitis 1
- Dupilumab (for atopic dermatitis) - associated with blepharitis in 32-55% of patients 1
Clinical Pitfalls
Do not confuse hordeolum with chalazion - while both involve eyelid gland obstruction, a chalazion is chronic lipogranulomatous inflammation without acute infection, whereas hordeolum is acute and purulent 5. Key differentiating features include redness, swelling, and pain being more prominent in hordeolum 6.
Beware of masquerading malignancy - marked asymmetry, resistance to therapy, or unifocal recurrent lesions warrant biopsy to exclude sebaceous carcinoma, particularly with focal lash loss or loss of normal eyelid margin anatomy 1.