Periocular infections are infections of the soft tissues surrounding the globe of the eye. These include infections of the eyelids, lacrimal system, and orbit.

EYELID INFECTIONS

Each eyelid contains a fibrous tarsal plate that gives structure to the lid. Within each tarsal plate are 20 to 25 vertical meibomian glands that secrete sebum at the lid margins. Glands of Zeis, smaller sebaceous glands adjacent to the lid-margin hair follicles, also secrete sebum. Sebum prevents ocular surface drying by slowing the rate of tear film evaporation.

Hordeolum

An internal hordeolum is an acute infection of a meibomian gland and presents as a tender, swollen nodule within the lid, pointing either to the skin or conjunctival surface. An external hordeolum (stye) is an acute infection of a gland of Zeis and points to the lid margin. Both are usually caused by Staphylococcus aureus and respond to frequent warm compresses and topical bacitracin or erythromycin ointment.

Chalazion

A chalazion is a nontender nodule within the lid that points to the conjunctival surface and is due to a sterile granulomatous reaction to inspissated sebum within a meibomian gland. Most chalazia resolve spontaneously within 1 month, but intralesional triamcinolone or incision and curettage may be used if conservative measures fail. Recurrences are common in patients with chronic blepharitis. Persistent or recurrent chalazia should be biopsied to exclude squamous cell carcinoma.

Marginal blepharitis

Marginal blepharitis is a diffuse inflammation of the lid margins and is usually due to hypersecretion of meibomian glands, although superinfection with S. aureus may play a role. Recurrent blepharitis is often associated with seborrheic dermatitis or rosacea. It may be treated with gentle lid scrubs and topical bacitracin; oral tetracycline may be helpful if there is associated rosacea. Unusual causes of blepharitis have included Pseudomonas, Capnocytophaga, herpes simplex virus, crab lice, and Demodex mites. Demodex infestations, characterized by cylindrical dandruff around the lashes, cause chronic blepharitis and may be treated by lid scrubs with tea tree oil.