Peripheral ulcerative keratitis

Summary

Peripheral ulcerative keratitis describes a group of inflammatory diseases involving the peripheral cornea. It is associated with autoimmune conditions such as rheumatoid arthritis, lupus and granulomatosis with polyangiitis. Symptoms include pain, redness, tearing, photophobia and decreased visual acuity. Signs include crescent-shaped damage of the cornea. Prompt diagnosis and treatment are essential to prevent complications and preserve vision.

Aetiology

Peripheral ulcerative keratitis is associated with chronic autoimmune diseases such as:

• Rheumatoid arthritis
• Systemic lupus erythematosus
• Granulomatosis with polyangiitis
• Relapsing polychondritis

These autoimmune disease can lead to an inflammatory response that can affect the cornea, leading to peripheral ulcerative keratitis.

Other conditions that can cause peripheral ulcerative keratitis include infectious diseases such as herpes simplex virus, varicella-zoster virus, and bacterial infections.

In some cases, peripheral ulcerative keratitis can be idiopathic.

Risk factors for developing PUK include a history of autoimmune disease, recent eye surgery or injury, contact lens use, and exposure to certain medications such as topical prostaglandins.

Clinical features

The clinical features of peripheral ulcerative keratitis typically involve inflammation and ulceration of the peripheral cornea. The condition can affect one or both eyes, and symptoms can vary in severity depending on the underlying cause and stage of the disease.

Common symptoms include:

• Blurred vision: corneal inflammation and ulceration can cause loss of visual acuity, causing vision to become blurry.
• Pain: peripheral ulcerative keratitis can cause moderate to severe eye pain, which may be described as a burning or stinging sensation.
• Photophobia: the eyes may be sensitive to light, causing discomfort in bright environments.
• Redness: The affected eye may appear red, inflamed, and bloodshot.
• Tearing: eyes may produce excessive tears, which can cause further irritation and discomfort.
• Eye discharge: the eyes may produce a thick, yellow discharge.
• Foreign body sensation.

Signs include:

• Peripheral corneal ulceration: lesion that develops in the peripheral (outer) portion of the cornea. The ulcer may be round or oval-shaped and can vary in size and depth. The ulcer can be visualised with fluorescein.
• Infiltrates: these are areas of inflammation and infiltration of white blood cells that can be seen around the corneal ulcer.
• Neovascularisation: formation of new blood vessels that grow into the cornea from the surrounding tissues. This can be a sign of chronic inflammation and can lead to scarring and vision loss.
• Corneal thinning: PUK can cause the cornea to become thin and weakened, which can increase the risk of corneal perforation.
• Conjunctival injection: this is redness and inflammation of the conjunctiva, which is the thin, transparent membrane that covers the white part of the eye.
• Decreased visual acuity: corneal inflammation and ulceration can cause vision to become blurred or decreased, especially if the central cornea is affected.

Diagnosis

• History: any autoimmune diseases, recent infections, or eye surgeries or injuries.
• Visual acuity: a reduced visual acuity is likely to favour the diagnosis.
• Slit-lamp examination: to assess for peripheral corneal ulceration, infiltrates, neovascularisation, conjunctival injection, anterior chamber reaction and corneal thinning.
• Fluorescein staining: using fluorescein dye in the eye to help visualise corneal ulcers and evaluate their size and depth.
• Blood tests: to check for underlying autoimmune diseases or infections that may be associated with PUK.
• Culture: it is important to exclude infectious causes such as ulcers due to bacteria, fungi and viruses. This can be done by performing a culture of the ulcer and eyelid margins.

Management

Local treatment:

• Topical: topical medications, such as corticosteroids or cyclosporine, may be prescribed to reduce inflammation and promote healing of the corneal ulcer.
• Lubrication: frequent use of artificial tears or other lubricating agents can help soothe the eye and reduce symptoms such as dryness and irritation.
• Bandage contact lenses: this may be used in some cases to control the inflammation of the corneal ulcer and promote healing.
• Surgery: If PUK is severe and has not responded to other treatments, surgical intervention may be necessary. Procedures such as amniotic membrane transplantation or corneal grafting may be considered.

Systemic treatment:

• Systemic immunosuppression: If PUK is associated with an underlying autoimmune disease, such as rheumatoid arthritis or systemic lupus erythematosus, systemic immunosuppression may be necessary. This involves the use of medications, such as corticosteroids, methotrexate, or cyclophosphamide, to suppress the immune system and reduce inflammation.
• Biologics such as rituximab may also be used. These drugs treat the keratitis as well as any underlying autoimmune disease.
• Other drugs that may be used include: collagenase inhibitors such as systemic tetracycline or topical 20% N-acetylcysteine.

References

1. ‘Peripheral Ulcerative Keratitis – Eye Disorders’. MSD Manual Professional Edition, https://www.msdmanuals.com/en-gb/professional/eye-disorders/corneal-disorders/peripheral-ulcerative-keratitis. Accessed 15 May 2022.