What Is Dendritic Keratitis?
Dendritic keratitis, also known as herpes simplex keratitis or epithelial keratitis, is a recurrent infection of the cornea caused by the herpes simplex virus. Herpes simplex virus (HSV) is easily transmitted, and in most cases, it spreads from one person to another through droplets. This virus can also be transmitted through direct inoculation but is less frequent. In most people, dendritic keratitis infection does not cause any permanent damage to the cornea, but in severe cases, there might be some scarring.
The most common type of HSV that is responsible for the infection of the cornea is HSV-1, which is also a type of herpes simplex virus that is responsible for causing cold sores in the mouth. Also, dendritic keratitis is considered to be one of the major causes of blindness throughout the world.
What is Viral Keratitis?
Viral keratitis is a comprehensive term that includes keratitis caused by a range of viruses, not just the herpes simplex virus. While herpes simplex keratitis represents a specific subtype within viral keratitis, other viruses, such as varicella-zoster and adenovirus, can also cause this inflammatory condition to affect the cornea. The diversity of viral causes shows the importance of proper identification for targeted treatment strategies.
What Is the Cause of Dendritic Keratitis?
Dendritic keratitis is caused by the herpes simplex virus (HSV). It is usually transmitted from one person to another and affects only human beings. In most cases, dendritic keratitis happens due to the reactivation of earlier infections. The commonest fact is that corneal infection occurs following another body part's infection. In most cases, another body part affected is the mouth.
The HSV virus is a double-stranded DNA virus with its core surrounded by a capsid in an icosahedron shape. There are two types of HSV virus: HSV-1 and HSV-2. HSV-1 is generally associated with infections that affect the orofacial region, whereas HSV-2 is associated with causing infections in the genitals.
What are the Symptoms and Signs of Herpes Simplex Keratitis?
Primary Infection:
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A feeling of a foreign body in the eye.
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Increased tear production.
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Sensitivity to light.
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Redness of the eye.
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Blistering of the eyelid in some cases.
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Worsening of symptoms.
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Blurred vision.
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Breakdown and healing of blisters within a week without scarring.
Recurring Infection
Recurring infections are further divided into three categories, which it includes:
Epithelial Keratitis (Dendritic Keratitis):
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Tearing.
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A sensation of a foreign body in the eye.
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Branching lesion on the corneal surface.
Localized Endothelitis (Disciform Keratitis):
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Discomfort.
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Sensitivity to light.
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Temporary and reversible vision loss.
Stromal Keratitis:
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Severe pain.
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Sensitivity to light.
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A feeling of a foreign body in the eye.
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Ulceration.
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Permanent scarring.
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Neovascularization.
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Thinning of the corneal stroma.
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Irreversible decrease in vision.
If a person is experiencing the above-explained symptoms, it is important to:
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Remove the contact lenses if they are wearing any.
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Wash the eyes frequently with water.
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Consult a doctor, as leaving it untreated could lead to blindness or loss of vision.
What Are the Various Risk Factors of Dendritic Keratitis?
The following are the risk factors of dendritic keratitis;
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Dendritic keratitis is recurrent, so people infected earlier by the herpes simplex virus are at a higher risk of getting it again.
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The risk gets higher for the people in the population who wear contact lenses.
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Certain studies have identified that some factors can increase the likelihood of disease reactivation.
They are:
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Increased body heat.
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Sunlight exposure.
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Menstruation.
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Stimulation of trigeminal nerve.
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Other infectious diseases.
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Some investigations have also shown that women are more susceptible to dendritic keratitis than men.
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Hormonal changes also significantly increase the risk of being affected by dendritic keratitis.
How Is Dendritic Keratitis Diagnosed?
Various laboratory tests can be performed to diagnose dendritic keratitis. Numerous dendritic epithelial ulcers on the terminal bulbs clinically mark the condition.
There can also be other infections, such as:
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Stromal edema.
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White blood cell infiltration of the sub-epithelium.
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Serologic testing might be used to diagnose dendritic keratitis, but it could be more helpful if the patient has already been affected by HSV infections. However, finding the presence of the herpes simplex virus could be helpful with cytological findings from the scrapping off.
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Conjunctivitis.
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Vesicular lesions.
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Impression cytology specimen.
Some of the other diagnostic procedures include the following:
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Fluorescent Antibody Testing - It involves impression cytology with the aid of a nitrocellulose membrane.
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Tzanck Smear Testing - It helps identify multinucleated cells and eosinophilic inclusion bodies.
How is Herpes Simplex Keratitis Treated?
The management of herpes simplex keratitis includes:
1. Pharmacological Treatment:
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The main treatment involves antiviral medications, and patients typically receive oral antiviral medications, such as acyclovir, valacyclovir, or famciclovir, for 10 to 14 days.
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Topical antiviral medications are employed to address the infection locally.
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A specific topical medication, Ganciclovir 0.15%, has been approved by the FDA for treating acute herpetic keratitis since 2009.
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This medication is applied five times a day until the corneal ulcer heals, followed by three times a day for an additional week.
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Trifluridine 1% is another topical option prescribed for dendritic keratitis.
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It is essential to discontinue its use within 10 to 14 days to prevent potential corneal toxicity.
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Topical steroids are contraindicated during active epithelial disease, cautioning against their use in these situations.
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Cycloplegia drops and topical antibiotics may be considered part of the treatment plan in specific cases.
2. Non-Pharmacological Treatment:
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Surgery: In cases of significant corneal trauma and scarring, a surgical procedure known as penetrating keratoplasty is performed to address the damage. The decision to undergo this surgery depends on factors such as the location and size of the scar. In certain situations, lamellar keratoplasty may be employed to enhance the clarity of the visual axis. Surgery is reserved for severe cases of extensive corneal scratching that leads to impaired vision. This option is considered when other treatments are insufficient to address the impact of the trauma on the cornea.
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Each case of dendritic keratitis is different. Hence, it is important to reach out to the doctor as early as possible to avoid serious eye and eyesight damage. Though some of these medications drastically reduce the signs and prevent the recurrence of the symptoms, they are only used as a management method since there is no permanent cure for dendritic keratitis.
How Can Dendritic Keratitis Be Prevented?
The following are some tips to prevent dendritic keratitis.
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The first and foremost step to having a healthy life is to be hygienic. This not only helps us against dendritic keratitis but also helps us be safe from all other infections.
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Dendritic keratitis is mainly transmitted through droplets; hence, avoiding unnecessary contact between unwashed hands and the eye is important.
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Proper care should be taken to keep the hands clean. Wash hands before and after touching any objects.
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As dendritic keratitis predominantly occurs following an oral infection, reach out to the doctor in case of cold sores to prevent them from spreading to the eyes.
Conclusion:
Dendritic keratitis is a serious condition that might be marked by recurrent infections. However, it can be prevented and treated if proper medical intervention is done. It can be managed extensively through oral and topical medications, but surgery happens to be the only course of treatment in cases of severe scarring. Even after surgery, antiviral medications might be prescribed to extend the survival rate of the grafts placed during the surgery and prevent further
