DDx ⬇
- Conjunctivitis (viral, bacterial, allergic)
- Uveitis
- Acute glaucoma
- Foreign body or corneal abrasion
- Keratitis (corneal ulcer or inflammation), eg, herpes simplex
- Scleritis or episcleritis
- Trauma
- Subconjunctival hemorrhage
- Eyelid disorder, eg, hordeolum, chalazion, blepharitis
- Cluster headache
Related DDx ⬆