Canthitis

Canthitis is inflammation of the canthus, the corner of the eye where the upper and lower eyelids meet. The canthus can be medial (toward the nose) or lateral (toward the ear). Inflammation may involve one side or both without affecting vision directly.

Symptoms typically include redness and swelling at the canthus, tearing, a gritty or irritated sensation, itching, and crusting around the eyelids. Discharge may be present, particularly with concomitant conjunctivitis, and the eye may feel tender or sensitive to light.

Causes are diverse. They include infectious agents (bacterial or viral conjunctivitis with focal canthal involvement), inflammatory skin conditions such as dermatitis around the eyelids, blepharitis, trauma or foreign body irritation, and less commonly fungal infections or autoimmune processes. Canthitis can be associated with canalicular disease affecting the lacrimal drainage system.

Diagnosis is usually clinical, based on eye examination. An ophthalmologist or clinician evaluates the canthal region, eyelids, conjunctiva, and lacrimal drainage. Tests may include swabs or cultures if discharge is prominent or recurrent, and imaging is rarely needed.

Treatment depends on the cause. Gentle lid hygiene, warm compresses, and lubrication are common measures. Bacterial infection may be treated with topical antibiotics applied to the lid margins or conjunctival sac. Inflammatory dermatitis or dermatitis-related canthitis may respond to topical steroids under supervision. Recurrent cases require specialist assessment.

Most canthitis improves with appropriate care, but persistent or recurring symptoms warrant evaluation for underlying lid disease or lacrimal system problems. Seek prompt care for severe pain, vision changes, fever, or rapidly worsening redness.