Differentiating Corneal Dendrites and Pseudodendrites: A Practical Guide for Early-Career Clinicians

Veatriki Athanasiou

Introduction

Corneal dendrites and pseudodendrites are branching epithelial lesions encountered in patients presenting with a painful red eye. Accurate differentiation is essential, as these lesions arise from distinct pathologies and require different management strategies. Misdiagnosis may result in inappropriate treatment and potentially sight-threatening complications. This article provides a practical guide for early-career clinicians, focusing on slit-lamp features, diagnostic pitfalls, and management implications (1-3).

Branching corneal lesions are commonly encountered in acute ophthalmology settings. Differentiating true corneal dendrites, most often caused by herpes simplex virus (HSV), from pseudodendrites is critical, as management differs substantially. For foundation doctors and early trainees, confidence in recognising these patterns is essential for safe clinical practice (1,2).

Pathophysiology

True corneal dendrites arise from active HSV replication within corneal epithelial cells, leading to linear branching ulcers (2,3). Pseudodendrites are not caused by epithelial viral replication and may be seen in herpes zoster ophthalmicus, neurotrophic keratopathy, healing epithelial defects, or topical drug toxicity (4,6).

Clinical Examination

True dendrites are thin, branching lesions with terminal end bulbs and a central ulcerated core. They stain brightly with fluorescein centrally, while rose bengal stains the virus-laden epithelial margins. Corneal sensation is often reduced (1-3). Pseudodendrites are typically broader, irregular, elevated lesions lacking terminal bulbs and often show minimal fluorescein staining. In herpes zoster ophthalmicus, they may appear as raised mucous plaques and are frequently associated with a dermatomal skin rash (4,6).

Management

HSV epithelial keratitis requires prompt topical antiviral therapy, and topical corticosteroids are contraindicated during the epithelial phase (2,5). Pseudodendrites, which are not caused by active HSV epithelial infection, do not benefit from HSV-directed topical antivirals. In cases of herpes zoster ophthalmicus, management instead centres on systemic antiviral therapy, with ocular treatment guided by associated inflammatory, neurotrophic, or secondary complications rather than the pseudodendritic lesion itself (4,6).

Where the diagnosis is uncertain, the clinical course is atypical, or there is poor response to initial treatment, early senior review is essential. Corneal sampling for microbiological culture and sensitivity should be considered in cases with significant epithelial defect, stromal involvement, contact lens wear, immunosuppression, or suspicion of microbial keratitis. This is particularly important before escalation to topical corticosteroids, as inappropriate treatment may worsen infectious disease and compromise visual outcomes (1,7).

Conclusion

Accurate differentiation between corneal dendrites and pseudodendrites is a key skill in acute ophthalmology. Careful slit-lamp examination and awareness of characteristic features enable early-career clinicians to initiate appropriate management and avoid sight-threatening complications (1,2).

References

  1. Kanski JJ, Bowling B. Kanski’s Clinical Ophthalmology: A Systematic Approach. 9th ed. Elsevier; 2020.
  2. Dart JKG. Herpes simplex keratitis. Br J Ophthalmol. 1988;72(8):565–575.
  3. Liesegang TJ. Herpes simplex virus epidemiology and ocular importance. Cornea. 2001;20(1):1–13.
  4. Liesegang TJ. Corneal complications from herpes zoster ophthalmicus. Ophthalmology. 1985;92(3):316–324.
  5. Wilhelmus KR. Antiviral treatment for HSV epithelial keratitis. Cochrane Database Syst Rev. 2015;(1):CD002898.
  6. American Academy of Ophthalmology. BCSC: External Disease and Cornea. 2022–2023.
  7. Ting DSJ, Ghosh S. Infectious keratitis: an update. Clin Exp Ophthalmol. 2019;47(6):670–678.

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