Causes of Styes (Hordeolum)
Styes are primarily caused by bacterial infections of the oil glands in the eyelids, most commonly by Staphylococcus aureus, which leads to inflammation and painful swelling of the eyelid margin.
Types and Pathophysiology
Styes (hordeola) can be classified into two main types:
- External hordeolum: Infection of the glands of Zeis or Moll at the base of the eyelashes
- Internal hordeolum: Infection of the meibomian glands deeper within the eyelid
The pathophysiology involves:
- Blockage of the oil gland opening
- Bacterial proliferation (primarily S. aureus)
- Inflammatory response
- Abscess formation
Risk Factors
Several factors increase the likelihood of developing styes:
Eyelid-Related Factors
- Blepharitis (chronic inflammation of the eyelid margins) 1
- Meibomian gland dysfunction (MGD) 2
- Poor eyelid hygiene allowing bacterial buildup 1
- Misdirected eyelashes (trichiasis) 2
Contact Lens Factors
- Improper contact lens hygiene 2, 1
- Overnight wear of contact lenses 2
- Contaminated contact lens solutions 2
- Extended wear beyond recommended schedule 2
Systemic Conditions
- Rosacea (patients with rosacea are more prone to developing styes) 2, 1
- Diabetes mellitus (increases susceptibility to infections) 2, 3
- Immunosuppression (from medications or medical conditions) 2, 1
- Seborrheic dermatitis 2
Other Contributing Factors
- Reusing contaminated eye makeup 1
- Touching eyes with unwashed hands 4
- Stress and hormonal changes (may exacerbate underlying conditions)
- Previous history of styes (recurrence is common) 1
Bacterial Etiology
The primary causative organism is Staphylococcus aureus, which:
- Normally colonizes the skin and can become opportunistic 4, 3
- Employs various virulence factors including cytolytic proteins and immune evasion molecules 4
- Can be internalized by skin keratinocytes, allowing it to evade antibiotic killing 5
- May be methicillin-resistant (MRSA) in some cases, complicating treatment 4
Prevention Strategies
To prevent styes:
- Practice good eyelid hygiene with daily cleansing 1
- Use warm compresses regularly (10-15 minutes, 3-4 times daily) 1
- Remove eye makeup completely before sleeping 1
- Replace contact lenses and cases after a stye resolves 1
- Avoid sharing eye makeup or towels
- Wash hands thoroughly before touching eyes
- Treat underlying conditions like blepharitis or rosacea 2, 1
Common Pitfalls and Caveats
Misdiagnosis: Styes can be confused with chalazia, which are non-infectious meibomian gland blockages that may require different treatment 6
Inadequate treatment: Many people don't complete the full course of treatment, leading to recurrence 1
Ignoring underlying conditions: Failing to address predisposing factors like blepharitis or rosacea can lead to chronic recurrence 2, 1
Self-squeezing: Attempting to "pop" a stye can spread infection and worsen inflammation 1
Antibiotic resistance: Standard antibiotics may not effectively eliminate S. aureus that has been internalized by keratinocytes 5
Delayed referral: Persistent styes (>2 months) should prompt ophthalmology referral 1
Understanding these causes and risk factors can help guide prevention strategies and appropriate treatment approaches for styes.