**4. Differential diagnosis**

Differential diagnosis is dependent on the corneal layer affected by the keratitis. Epithelial keratitis should be differentiated with epithelial regeneration line

## *Recent Advances in the Diagnosis and Management of Herpetic Keratitis DOI: http://dx.doi.org/10.5772/intechopen.96898*

after traumatic epithelial defect, epithelial corneal dystrophies, such as epithelial basement membrane corneal dystrophy (EBMCD; map-finger-dot dystrophy, Cogan microcystic dystrophy), epitheliopathy associated with excessive contact lens wear or iatrogenic epitheliopathy after topical drops containing preservatives. Stromal involvement requires differentiation with other microbial keratitis (bacterial, fungal or amoebic), vaccinia virus keratitis (VACVK), Varicella Zoster virus keratitis, Thygeson superficial punctate keratopathy, stromal or Bowman layer corneal dystrophies, such as TGFBI corneal dystrophies. Marginal keratitis should be differentiated with other forms of marginal ulcers, such as staphylococcal marginal keratitis or related to atopic or autoimmune diseases, such as rheumatoid arthritis, systemic lupus or granulomatosis with polyangiitis (GPA). Also, neurotrophic keratitis may be initiated by multiple other causes, such as surgical and laser procedures, chemical burns, excessive contact lens wear and preservative-containing topical medicines, diabetes mellitus, multiple sclerosis and congenital or acquired abnormalities of the trigeminal nerve. Examples of the diseases, which require differential diagnosis with HSV keratitis are presented in **Figure 8**.

#### **Figure 8.**

*Representative images of the slit-lamp photograph of the different forms of corneal diseases, which should be differentiated with HSV-keratitis. (A) Slit-lamp photograph of the epithelial basement membrane corneal dystrophy (EBMCD; map-finger-dot dystrophy, Cogan microcystic dystrophy). Superficial white dots visible. (B) The slit lamp photograph after fluorescein installation under blue light with additional yellow barrier filter of the patient 9A. An irregular area of the disrupted epithelium visible. (C) Slit-lamp photograph of the lattice corneal dystrophy (LCD). A dystrophy was confirmed by the TGFBI gene testing, which revealed a H626R mutation. (D) Slit-lamp photograph of the pediatric form of the lattice corneal dystrophy (LCD). Epithelial haze with multiple small, gray dots is visible. A dystrophy was confirmed by the TGFBI gene testing, which revealed a R124C mutation.*
