Differential Diagnosis for Corneal Abrasion vs Herpes Simplex Keratitis
To distinguish between corneal abrasion and Herpes simplex keratitis, it's crucial to consider the clinical presentation, history, and diagnostic findings. Here's a structured approach to the differential diagnosis:
Single Most Likely Diagnosis:
- Corneal abrasion: This is often the first consideration due to its high prevalence and the common presentation of pain, redness, and a history of trauma or contact lens use. The symptoms and signs can overlap with those of Herpes simplex keratitis, but the absence of specific findings like dendritic ulcers may lean the diagnosis towards a corneal abrasion.
Other Likely Diagnoses:
- Herpes simplex keratitis: Characterized by dendritic ulcers, which are pathognomonic for this condition. The presence of these ulcers, along with symptoms like pain, redness, and blurred vision, especially in a patient with a history of recurrent episodes, makes this a likely diagnosis.
- Bacterial keratitis: This condition can present similarly to corneal abrasion and Herpes simplex keratitis, with symptoms including pain, redness, and decreased vision. A history of contact lens use or trauma increases the risk.
- Fungal keratitis: More common in agricultural workers or those who have suffered an injury involving organic matter. It tends to have a slower onset and may be associated with a history of trauma with a vegetable or organic matter.
Do Not Miss Diagnoses:
- Acute angle-closure glaucoma: Although it presents differently, with severe pain, redness, decreased vision, headache, and nausea, it's a medical emergency that requires immediate attention. Missing this diagnosis can lead to permanent vision loss.
- Scleritis: An inflammatory condition of the sclera that can mimic the pain and redness of other conditions but is typically more severe and can be associated with systemic diseases.
Rare Diagnoses:
- Acanthamoeba keratitis: A rare but serious infection of the cornea caused by a protozoan parasite, often associated with contact lens use, especially with poor hygiene or exposure to contaminated water.
- Varicella-zoster virus keratitis: Similar to Herpes simplex but caused by the varicella-zoster virus, presenting with a dermatomal distribution of the rash and potentially serious ocular complications.