Chalazion is a chronic, non-infectious lipogranulomatous inflammation of a meibomian gland in the upper or lower eyelid (or less commonly the smaller Zeis gland of an eyelash follicle). The meibomian glands are modified sebaceous glands within the tarsal plate that produce the lipid component of tear film. Obstruction of the gland duct causes accumulation of lipid contents that eventually extravasate into surrounding stroma, triggering a granulomatous inflammatory response with macrophages, lymphocytes, and giant cells. Unlike hordeolum (which is an acute infection of glands of Zeis or Moll causing painful, erythematous swelling), chalazion is non-infectious and presents as painless, gradual swelling.
Risk factors include conditions associated with meibomian gland dysfunction such as rosacea, blepharitis, seborrheic dermatitis, and oily skin. Hormonal changes, certain medications (oral retinoids), and viral infections may also predispose. Recurrence in the same location is unusual; recurrence after appropriate management raises concern for sebaceous gland carcinoma, an aggressive malignancy of the eyelid that can mimic chalazion. Sebaceous gland carcinoma should be considered in older patients with recurrent or atypical chalazia, lesions on the upper eyelid (more common location), persistent eyelash loss, induration extending beyond the gland, and any chalazion that fails appropriate treatment.
Clinical presentation includes a painless, slowly enlarging, firm subcutaneous nodule of the eyelid, often visible as a localized swelling beneath the skin or as a granuloma on the conjunctival surface (when palpebral conjunctiva is everted). Vision is typically unaffected unless the chalazion is large enough to cause mechanical ptosis or astigmatism from corneal indentation. Conservative management is first-line: warm compresses applied for 10-15 minutes 3-4 times daily soften gland contents and promote drainage; lid massage helps express obstructed material; eyelid hygiene with diluted baby shampoo or commercial lid scrubs reduces colonization; and topical antibiotic-corticosteroid combinations may be used for associated blepharitis or secondary infection. Most chalazia (60-80%) resolve with conservative therapy within 1-2 months. For persistent lesions, intralesional triamcinolone acetonide injection (0.05-0.2 mL of 10-40 mg/mL) shows resolution in 60-80%, with risk of skin atrophy and depigmentation, particularly in pigmented patients. Surgical incision and curettage is performed for refractory chalazia, typically through transconjunctival approach with vertical incision to avoid eyelash follicles. Histopathologic examination of curettings is recommended for atypical or recurrent lesions to exclude malignancy.