What is Peripheral Ulcerative Keratitis?
Peripheral ulcerative keratitis (PUK) is a condition that affects the area around the edge of the cornea, which is the clear outer layer at the front of the eye. This condition typically appears as damage to the eye’s surface and a loss of the cornea’s substance. The causes could be local or general, linked to an infection or not. PUK can also be caused by inflammatory diseases that affect blood vessels and connective tissues; diseases such as rheumatoid arthritis, granulomatosis with polyangiitis, and systemic lupus erythematosus account for about 53% of PUK cases.
A particular kind of PUK, known as Mooren’s ulcer, is not linked to any specific systemic disease and contributes to 31.5% of PUK cases. This was first described in the mid-19th century as an ulcer (or open sore) on the cornea. This kind of ulcer starts at the edge of the cornea and moves towards the center, creating a distinctive protruding edge.
PUK is important to identify as it can be an early symptom of a serious systemic disease. Thorough medical examination and coordinated management between different healthcare providers are necessary to ensure patients’ safety.
Recognizing PUK when a patient is experiencing scleritis, an inflammation of the white part of the eye, is a bad sign. The gradual destruction of the cornea’s substance can lead to a hole in the cornea. If the patient already has an autoimmune disease, this indicates significant potential for disease and death.
What Causes Peripheral Ulcerative Keratitis?
Table 1 lists a range of eye (local) and body-wide (systemic) issues that can cause Peripheral Ulcerative Keratitis (PUK). This is a serious condition that affects your eye, specifically the outer part known as the cornea. Around half of all non-infectious PUK cases are linked to a connective tissue disorder, the most common one being rheumatoid arthritis (RA). In people with RA, PUK often affects both eyes and becomes more prevalent in the late stages of RA. Studies show that RA is associated with 34% of eyes with non-infectious PUK. PUK can also frequently be a symptom of Granulomatosis with Polyangiitis (GPA), a condition that can cause inflammation and damage in the blood vessels of your sinuses, nose, throat, lungs, and kidneys. In PUK cases linked to GPA, the cause is necrotizing vasculitis, which is inflammation damaging the blood vessels near the eye.
Infections can happen in the peripheral cornea (the outer layer of the eye’s front) without it being classified as PUK. PUK is recognized by the thinning of the corneal tissue in a crescent shape, inflammatory cells present in the cornea close to the colored part of the eye (the limbus), and the presence of damage to the outer layer of the cornea (epithelial defect). Ruling out infection as a cause is important, as it accounts for almost 20% of all PUK cases. Many organisms including bacteria, viruses, fungi, and Acanthamoeba spp, etc., can cause PUK.
Systemic and ocular causes of PUK can range from infections like chickenpox or syphilis, autoimmune conditions like rheumatoid arthritis or lupus, and other conditions such as cancer or gout. Infections like Staphylococcus or Herpes, autoimmune conditions like Mooren’s ulcer, and trauma such as chemical injuries can also cause PUK.
One type of condition related to PUK is Mooren Ulcer. It’s often linked to severe pain and complications can include inflammation inside the eye, secondary infection, cataracts, increased eye pressure (or glaucoma) and corneal perforation, which occurs in 35-40% of patients. It can occur in three different forms: Type 1 which commonly affects older women in one eye; type 2 which is more aggressive initially and seen in young males in both eyes; and type 3 which is more common in people in their mid-50s with no particular gender preference. The severity of the pain, progression speed, likelihood of relapse, and development of complications vary with each type.
Risk Factors and Frequency for Peripheral Ulcerative Keratitis
In the UK, Peripheral Ulcerative Keratitis (PUK) affects about 0.2 to 3 people per million each year. This condition generally affects females more often, but Mooren ulcers, a specific type of PUK, occur more in males. There is no strong evidence indicating that PUK affects any racial or ethnic group more than another, but this may depend on the cause of the condition. Likewise, the age of a person when they first experience PUK can vary based on the underlying cause. Doctors usually classify PUK based on clinical findings, which helps them decide what types of tests and treatments to use for targeting the cause of the condition.
- In the UK, PUK affects 0.2 to 3 people per million each year.
- PUK usually affects females more, but Mooren ulcers (a type of PUK) occur more in males.
- No strong evidence suggests that PUK affects any racial or ethnic group more than another.
- The age when a person first experiences PUK can vary based on its underlying cause.
- Doctors typically diagnose and classify PUK based on clinical findings to help determine the most appropriate tests and treatments.
Signs and Symptoms of Peripheral Ulcerative Keratitis
Peripheral ulcerative keratitis (PUK) is an eye condition, which typically affects one eye but sometimes can affect both. It’s often linked with systemic diseases. Someone with PUK may have various symptoms such as:
- Eye pain
- Sensitivity to light (photophobia)
- Excessive tear production
- Eye redness
- Changes in vision, which can range from mild to severe
The primary signs of PUK involve a specific pattern of eye damage and inflammation. This includes a crescent-shaped ulcer on the periphery of the eye, an epithelial defect (damage to the outer layer of the eye), loss of the cornea’s substance (stroma), and infiltration of the limbus (the border area between the cornea and the white part of the eye).
If PUK is linked to a systemic disease, the inflammation can also spread to surrounding structures of the eye, including the conjunctiva (the tissue covering the front of the eye), episclera (the outer layer of the white part of the eye), and the sclera (the white part of the eye).
Continuing inflammation can lead to the cornea’s thinning and, if left untreated, can lead to an emergency condition called corneal perforation, where the iris tissue becomes visible through a hole in the cornea. PUK can also lead to irregular astigmatism, scarring, and reduced vision over time.
Mooren’s ulcer is a specific variety of PUK which has no known cause. There are three different known types of clinical presentations of Mooren’s ulcer.
It’s usually possible to pinpoint the cause of PUK through a detailed medical history and physical examination. This would involve asking the patient about signs and symptoms affecting the whole body, the muscles and joints, digestion, breathing, skin, heart, and nervous system.
Testing for Peripheral Ulcerative Keratitis
Physicians use a careful physical examination to look for signs that can point to the cause of an illness. For example, if they find bumps under the skin of your arms and legs, that and a couple of blood tests can indicate you might have rheumatoid arthritis, a common cause of a certain type of eye inflammation known as peripheral ulcerative keratitis (PUK).
Another sign they may look for is changes in the shape of your nose and your outer ears, like a “saddle nose” appearance or abnormal ear shape. These could suggest a condition called relapsing polychondritis, an inflammation that affects the cartilage in various parts of the body and repeatedly comes and goes.
There are also certain physical signs that can indicate the presence of a disease called systemic lupus erythematosus (SLE). These may include ulcers in your mouth, a red rash on the face, changes in skin color on the face and scalp, or hair loss. In addition, if you’re experiencing headaches located around your temples accompanied by pain when chewing, this could be a sign of giant cell arteritis, a condition that inflames the arteries on both sides of your head.
Another symptom, known as Raynaud’s phenomenon, where fingers or toes turn white or blue when cold, can be present in SLE, Sjögren’s syndrome (a condition that affects tear and saliva glands), and a disease called progressive systemic sclerosis that causes skin tightening and organ damage.
Lastly, a condition called granulomatosis with polyangiitis (GPA) commonly appears between the ages of 40-50 and is more common in men. It causes a unique combination of inflammation and damage in the respiratory tract and the kidneys, leading to a particular kind of kidney disease known as focal segmental glomerulonephritis.
Treatment Options for Peripheral Ulcerative Keratitis
Managing Peripheral Ulcerative Keratitis (PUK), a condition that involves the inflammation of the edge of the cornea (the clear, round dome covering the eye’s iris and pupil), requires a customized approach. The main goal is to restore the healthy surface of the eye, prevent any further damage, and protect against further infections. For cases where the PUK is not caused by an infection, doctors often use a mix of eye drops for lubrication, steroids, and oral steroids with substances known as collagenase inhibitors, which help to prevent further harm to the eye. However, the use of steroids can be controversial, especially if there’s an existing immune system disorder, as they could increase the risk of damage to the cornea. In that case, they are used carefully, and only if necessary.
System-wide medications to suppress the immune system can require about 4 to 6 weeks to show their effect, and during this period, oral steroids may be necessary. If there’s an existing localized or system-wide infection, appropriate antimicrobial medications should be used. A sample from the cornea might be taken for lab analysis to understand what is causing the PUK to start appropriate treatment. If a particular type of bacteria is detected, the treatment can be adjusted accordingly.
Where PUK is caused by conditions like Rheumatoid Arthritis or Granulomatosis with Polyangiitis, a remission strategy using steroids along with certain cytotoxic agents like methotrexate is generally employed. Other possible medications include azathioprine and cyclophosphamide. In severe cases, rituximab can be used as a last resort medication. With a condition like Systemic Lupus Erythematosus, systemic corticosteroids are also used along with a cytotoxic agent.
In younger patients, methotrexate is a first-choice treatment if there’s an underlying disease. In these cases, cyclosporine can be considered if initial treatments are not effective. It’s important to note that some of these drugs can harm the fetus in pregnant women and should be avoided.
In rare cases, the condition is caused by a type of ulcer known as Mooren’s ulcer. Management generally starts with topical corticosteroids and cyclosporine, then progresses to surgical options. Hepatitis C infection may lead to this type of PUK, and treatment using interferon α2b can help resolve the ulceration.
Surgery can sometimes lead to PUK returning or the graft being rejected, and therefore, it’s put on hold until the inflammation is under control. Despite this, multiple grafts might be required in many patients. The size of the corneal defect determines the surgical technique selected. The surgical management of PUK can include methods such as amniotic membrane transplant, conjunctival resection, and lamellar patch grafts. Corneal glue might also be used for smaller perforations that are less than 3mm in diameter.
What else can Peripheral Ulcerative Keratitis be?
When diagnosing eye conditions associated with a thinning or clouding of the peripheral cornea, it’s important to consider a range of other diseases that might be causing similar symptoms. Conditions to consider include:
- Staphylococcal marginal keratitis
- Phlyctenulosis
- Vernal keratoconjunctivitis
- Infectious keratitis
- Exposure keratitis
- Trichiasis
- Lid malpositions
- Terrien marginal degeneration
- Pellucid marginal degeneration
- Senile furrows
In marginal keratitis, you can often see a clear part of the cornea between the edge of the cornea and the inflamed areas. Peripheral corneal degenerations, on the other hand, are not linked with inflammation, show no sign of infiltrates, and feature an untouched surface layer of the cornea.
What to expect with Peripheral Ulcerative Keratitis
Patients who have system-wide health issues and who are diagnosed late with this disease tend to have more severe health outcomes and a higher risk of death. The simultaneous presence of scleritis (inflammation of the white part of the eye) and PUK (a type of inflammation of the cornea) often indicates a negative outcome for both eye health and overall health.
The perforation or puncture of the cornea (the clear front surface of the eye) results in poor vision even after treatment– 65% of people have vision limited to counting fingers or worse. Corneal perforation is also linked to a higher risk of death within a year: 24% in the case of unilateral (affecting one eye) and 50% in bilateral (affecting both eyes) corneal perforation cases.
Possible Complications When Diagnosed with Peripheral Ulcerative Keratitis
The biggest problem to eyes can be corneal perforation. This can happen in both eyes, and seriously affect final eyesight, possibly leading to loss of vision. The condition PUK can also lead to death, especially when there’s a perforation in any or both eyes.
Possible complications:
- Corneal perforation in either or both eyes
- Significant impact on final eyesight
- Potential total loss of vision
- Systemic complications due to PUK
- Increased risk of death, particularly resulting from eye perforation
Preventing Peripheral Ulcerative Keratitis
Peripheral ulcerative keratitis is a serious eye condition that requires immediate medical attention, as it could lead to a hole in the front part of the eye (corneal perforation) and possibly even blindness. It’s crucial to have a team of different specialists working together to diagnose and treat this condition. Because of its severity, treatment often involves long-term use of medications that suppress the immune system, but these can also have negative side effects. Moreover, this condition can come back even after treatment, so it’s important to have a clear treatment plan and good communication between the patient and the medical team to ensure safe recovery.
