Chalazion Pathophysiology
A chalazion develops from chronic lipogranulomatous inflammation caused by obstruction of the meibomian glands (deep chalazion) or Zeis glands (superficial chalazion) in the eyelid tarsal plate, leading to retained sebaceous secretions and subsequent granulomatous reaction. 1
Primary Mechanism: Glandular Obstruction and Lipid Retention
The fundamental pathophysiologic process begins with obstruction of the sebaceous glands of the eyelid:
- Meibomian gland dysfunction (MGD) is the underlying driver, characterized by altered biochemical composition of meibomian gland secretions 2
- Obstruction leads to plugging of meibomian orifices with secretions ranging from turbid fluid to thick cheese-like material 2
- Retained lipid secretions accumulate within the gland, triggering a chronic inflammatory response 1
- This is a non-inflammatory/non-infectious process initially, distinguished from the acute purulent infection seen in hordeola 1
Secondary Inflammatory Response
Once obstruction occurs, a cascade of inflammatory changes develops:
- Lipogranulomatous inflammation forms as the immune system reacts to the trapped sebaceous material 1
- The chalazion manifests as eyelid findings including pouting or plugging of meibomian orifices, thickening and scalloping of the eyelid margin, and prominent blood vessels crossing the mucocutaneous junction 2
- Chronic inflammation can lead to eventual atrophy and fibrosis of the meibomian glands in the affected area 2
- Meibomian gland loss occurs in the chalazion area, with the extent of loss corresponding to the size of the chalazion itself rather than the treatment method employed 3
Associated Meibomian Gland Dysfunction
The broader context of MGD contributes to chalazion formation:
- Decreased availability of normal meibum to the lid margin and tear film results from MGD 2
- This leads to hyperosmolarity and instability of the tear film, increased bacterial growth on the lid margin, evaporative dry eye, and ocular surface inflammation 2
- While the microbiome differs between patients with chalazion and healthy controls, conventional bacterial cultures typically show no growth, supporting the non-infectious nature 4
Clinical Implications
Understanding the pathophysiology reveals important clinical considerations:
- Chalazia represent a continuum with blepharitis and MGD, often occurring in patients with coexisting rosacea or seborrheic dermatitis 2
- Recurrent chalazia may indicate underlying systemic conditions such as subclinical hypothyroidism or persistent MGD requiring targeted therapy 5
- The range of meibomian gland loss corresponds to the chalazion size, not the treatment modality, emphasizing the importance of early intervention 3