Herpes simplex keratitis

Herpes simplex keratitis
Other namesHerpetic keratoconjunctivitis, herpesviral keratitis
Dendritic corneal ulcer.jpg
Dendritic corneal ulcer after fluorescein staining

Herpetic simplex keratitis is a form of keratitis caused by recurrent herpes simplex virus (HSV) infection in the cornea.[1]

It begins with infection of epithelial cells on the surface of the eye and retrograde infection of nerves serving the cornea.[2] Primary infection typically presents as swelling of the conjunctiva and eyelids (blepharoconjunctivitis), accompanied by small white itchy lesions on the corneal surface. The effect of the lesions varies, from minor damage to the epithelium (superficial punctate keratitis), to more serious consequences such as the formation of dendritic ulcers.[3] Infection is unilateral, affecting one eye at a time. Additional symptoms include dull pain deep inside the eye, mild to acute dryness, and sinusitis. Most primary infections resolve spontaneously in a few weeks. Healing can be aided by the use of oral and topical antivirals.

Subsequent recurrences may be more severe, with infected epithelial cells showing larger dendritic ulceration, and lesions forming white plaques.[3] The epithelial layer is sloughed off as the dendritic ulcer grows, and mild inflammation (iritis) may occur in the underlying stroma of iris. Sensation loss occurs in lesional areas, producing generalised corneal anaesthesia with repeated recurrences.[3] Recurrence can be accompanied by chronic dry eye, low grade intermittent conjunctivitis, or chronic unexplained sinusitis. Following persistent infection the concentration of viral DNA reaches a critical limit. Antibody responses against the viral antigen expression in the stroma can trigger a massive immune response in the eye. The response may result in the destruction of the corneal stroma,[3] resulting in loss of vision due to opacification of the cornea. This is known as immune-mediated stromal keratitis.

HSV infection is very common in humans. It has been estimated that one third of the world population have recurrent infection. Keratitis caused by HSV is the most common cause of cornea-derived blindness in developed nations. Therefore, HSV infections are a large and worldwide public health problem.[4] The global incidence (rate of new disease) of herpes keratitis is roughly 1.5 million, including 40,000 new cases of severe monocular visual impairment or blindness each year.[5]

  1. ^ James, William D.; Berger, Timothy G. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. p. 370. ISBN 978-0-7216-2921-6.
  2. ^ Carr DJ, Härle P, Gebhardt BM (May 2001). "The immune response to ocular herpes simplex virus type 1 infection". Experimental Biology and Medicine. 226 (5): 353–66. doi:10.1177/153537020122600501. PMID 11393165.
  3. ^ a b c d Suresh PS, Tullo AB (September 1999). "Herpes simplex keratitis". Indian Journal of Ophthalmology. 47 (3): 155–65. PMID 10858770.
  4. ^ Cite error: The named reference yanoff was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference farooq was invoked but never defined (see the help page).