The eyelids contain various glands (meibomian, Zeis, and Moll glands), the secretions of which serve as components of the tear film and aid in the lubrication of the eyelids. Bacterial infections or accumulation/dysregulation of secretions can result in three common inflammatory conditions of the eyelid: hordeolum (stye), blepharitis, and chalazion. A hordeolum is an acute eyelid inflammation (usually infectious) associated with painful, erythematous, and pus-filled nodules. Blepharitis is a chronic (usually infectious) inflammatory condition associated with crusty, scaly plaques, and/or oily deposits on the margins of the eyelids. A chalazion is a focal sterile granulomatous swelling of the eyelid's sebaceous gland and may result from either a hordeolum or blepharitis. Diagnosis is usually clinical. Treatment depends on the particular condition and includes eyelid hygiene, topical antibiotics if an infectious etiology is suspected, or surgery.
- Definition: common acute inflammation of the tear gland or eyelash follicles (Zeis or meibomian glands)
- Clinical features
- Diagnostics: usually a clinical diagnosis
- Treatment: Most styes are self-limiting and resolve spontaneously after 1–2 weeks.
- Definition: Blepharitis is a common eyelid condition that presents as a chronic and/or recurrent inflammation with scaling of the eyelid margins.
- Staphylococci (most common causative pathogen)
- Other infective etiologies: viral (e.g., herpes simplex or varicella zoster) or parasitic ( or ). 
Allergic reactions or anatomical obstruction of sebaceous glands
- Endogenous factors: oily deposits, seborrhea, hypersecretion of the eyelid glands, accumulation of secretion from the meibomian glands
- External factors: smoke, dust, dry indoor climate, chemicals, drug toxicity
- Systemic diseases: rosacea, atopy, and seborrheic dermatitis
- Ocular diseases: dry eye syndromes (e.g., ), chalazion, trichiasis, conjunctivitis, and keratitis
- Anterior blepharitis: inflammation of the anterior margin of the eyelids, involving the skin, eyelashes, and follicles
- Posterior blepharitis: inflammation of the posterior margin of the eyelids; associated with meibomian gland dysfunction and/or obstruction (meibomitis) as well as abnormalities of the tarsal plate
- Chronic or recurrent red, swollen eyelids and irregular eyelid margins
- Crusty, scaly plaques, and/or oily deposits on the eyelid margin and eyelashes
- Eye irritation and visual abnormalities
- Diagnostics: clinical diagnosis
- Definition: focal granulomatous swelling of the sebaceous glands without necrosis, which is primarily caused by obstruction of the glands
- Clinical features