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Sunday, December 19, 2010

Herpex Simplex Blepharitis  

SIGNS AND SYMPTOMS
Signs and Symptoms: Herpes simplex virus (HSV) infections involving the lid may present in one of two forms. The classic appearance involves an accumulation of small vesicles or pustules along the lid margin and/or periocular skin. These lesions typically have an inflamed, erythematous base. Within the first week of infection, the vesicles may ulcerate or harden into crusts.

A second “erosive-ulcerative” form of HSV blepharitis has also been described. This presentation is characterized by erosions of the lid at the Gray line or ulcers along the lid margin, or a combination of both. The lid typically displays generalized swelling and redness associated with these lesions.

HSV blepharitis is encountered primarily in children, although adults may also manifest this disorder. Presenting symptoms include pain and tenderness upon palpation, as well as increased lacrimation in severe cases. If the conjunctiva is involved, tarsal follicles may be observed along with bulbar injection and chemosis. Swollen pre-auricular nodes (pre-auricular lymphadenopathy) on the involved side is common.


PATHOPHYSIOLOGY
Herpes simplex is actually the most common virus found in humans. A member of the Herpetoviridae family, HSV is a double-stranded DNA virus that replicates within cell nuclei. As it leaves the host cell, it becomes encapsulated and can lie dormant for extended periods. Several trigger factors, including fever, trauma, emotional stress, menstruation, exogenous immunosuppressive agents, and overexposure to UV radiation can activate the virus. Transmission typically occurs by direct contact with an open epithelial lesion or contaminated bodily secretions. Rarely, the virus may be spread by contaminated materials such as towels or tissues.

Primary ocular infections occur most often in children between the ages of 6 months and 5 years, and almost invariably present as blepharitis or blepharoconjunctivitis. In recurrent attacks, the virus usually reappears as a dendritic keratitis. Several reports of recurrent HSV blepharitis have been reported in the literature, however.

MANAGEMENT
There is no specific treatment for HSV blepharitis, and most often the course of the disease is self-limiting. The use of warm saline compresses with a topical drying agent (e.g. 70% alcohol) is usually sufficient to palliate the patient. If the lesions are extensive, concomitant use of topical antibiotic ointment is prudent to prevent a secondary opportunistic bacterial infection. The use of topical or oral antiviral agents has not been proven to enhance the recovery of patients with HSV blepharitis, although it is advocated by some practitioners for more severe cases. However, topical trifluridine (Viroptic 1%) is absolutely indicated in cases presenting with corneal involvement.

The use of topical steroids on HSV lid lesions may be unwise, particularly if there is other ocular involvement. Although corticosteroids may be used without fear in cases of herpes zoster (HZO) blepharitis, their use in cases of HSV infection may predispose the patient to the eruption of a dendritic keratitis.

CLINICAL PEARLS

• Always include HZO in the differential diagnosis of HSV blepharitis. Keep in mind, however, that HZO typically affects elderly patients over the age of 70. Younger patients who present with HZO are often immunocompromised secondary to disorders such as AIDS or lymphoma. HSV blepharitis is usually encountered in children, but can occur at any age.

• Although herpes simplex is known as a sexually transmitted disease, the vast majority of ocular herpes infections are not contracted via sexual contact. This is very important to recognize when considering pediatric cases of HSV blepharitis.

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