Introduction

Keratoconjunctivitis refers to the simultaneous inflammation of the conjunctiva and the cornea, often presenting with symptoms such as redness, photophobia, tearing, and blurred vision. In immunocompetent individuals, it is usually caused by common pathogens and follows a self-limiting course. In contrast, immunocompromised patients, including those with HIV/AIDS, cancer, post-transplant status, or those on long-term immunosuppressive therapy, face a broader spectrum of pathogens and more severe disease courses, often leading to complications such as corneal ulcers, scarring, and vision loss if not appropriately managed.¹

Pathophysiology and immunosuppression

The ocular surface is protected by both physical barriers and immune mechanisms. Tear film contains antimicrobial peptides like lactoferrin and lysozyme, while conjunctival and corneal epithelial cells actively participate in immune surveillance. In immunocompromised individuals, these defences are weakened. 

Impaired cell-mediated immunity particularly predisposes these patients to viral, fungal, and protozoal infections.² For example, individuals with HIV often present with ocular manifestations due to opportunistic infections, with keratoconjunctivitis being one of the early signs. Chemotherapy and immunosuppressive drugs also lead to increased susceptibility to pathogens such as cytomegalovirus (CMV), herpes simplex virus (HSV), and fungi.³

Etiology

Viral causes

• Herpes Simplex Virus (HSV): HSV keratoconjunctivitis is more aggressive in immunocompromised patients and often recurs⁴
• Cytomegalovirus (CMV): CMV keratitis is rare but can occur in severely immunocompromised patients, especially those with AIDS⁵
• Adenovirus: While common in healthy individuals, adenoviral keratoconjunctivitis can become chronic and severe in individuals with compromised immune systems⁶

Bacterial causes

• Pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae can cause rapidly progressing bacterial keratitis, particularly in neutropenic patients⁷

Fungal causes

• Candida, Aspergillus, and Fusarium species are more prevalent in patients with neutropenia or those on corticosteroid therapy⁸

Parasitic and protozoal causes

• Acanthamoeba and Toxoplasma gondii have been implicated in keratoconjunctivitis in patients with AIDS and post-transplant immunosuppression⁹

Risk factors

• HIV/AIDS
• Organ transplantation
• Haematologic malignancies
• Chemotherapy and radiotherapy
• Corticosteroid use
• Autoimmune diseases or immunomodulators
• Diabetes mellitus

Each of these conditions disrupts the normal immune surveillance of the ocular surface, allowing opportunistic infections to proliferate.

Clinical presentation

Symptoms in immunocompromised patients may mimic common conjunctivitis but are often more severe:

• Redness and photophobia
• Watery or purulent discharge
• Visual impairment
• Pain or foreign body sensation
• Corneal ulcers or stromal infiltrates

In some cases, the immune response may be blunted, leading to atypical or muted symptoms. This makes early diagnosis difficult and necessitates high clinical suspicion.¹⁰

Diagnostic approach

1. Clinical examination
   • Slit-lamp biomicroscopy to evaluate corneal involvement
   • Fluorescein staining to detect epithelial defects
2. Microbiological testing
   • Conjunctival and corneal scrapings for Gram stain, KOH mount, and cultures
   • PCR testing for viral DNA (e.g., HSV, CMV)
   • Confocal microscopy for Acanthamoeba
3. Systemic evaluation
   • CD4 count in HIV-positive patients
   • CBC, blood cultures, and imaging in cases with systemic symptoms

Early identification of the causative organism is crucial to initiating appropriate therapy and avoiding complications.

Management strategies

Empiric antimicrobial therapy

Empiric treatment must be broad-spectrum and tailored based on microbiological findings. In severe cases, hospitalisation and parenteral antibiotics may be necessary.

• Antiviral agents: Acyclovir or Ganciclovir for HSV/CMV
• Antibacterial agents: Fluoroquinolones or fortified antibiotics like vancomycin and tobramycin
• Antifungals: Natamycin for filamentous fungi; amphotericin B for yeasts

Adjunctive therapies

• Topical corticosteroids: Used with caution due to immunosuppression, only after microbial control is established
• Lubricants: To protect the ocular surface and promote healing
• Cycloplegics: For pain relief and prevention of synechiae

Systemic immune modulation

For patients with modifiable causes of immunosuppression (e.g., corticosteroid-induced), tapering or altering immunosuppressive regimens may be considered in consultation with the primary care team or relevant specialists.

Surgical interventions

• Debridement for fungal or herpetic keratitis
• Amniotic membrane transplantation in cases of persistent epithelial defects
• Penetrating keratoplasty in cases with corneal perforation or scarring

Prevention

Preventive strategies are critical, particularly in high-risk populations:

• Routine eye examinations in patients with HIV or post-transplant
• Patient education on hygiene and early symptom reporting
• Avoidance of contact lens use in immunocompromised states unless essential
• Prophylactic antivirals in transplant patients with prior HSV infection

Special considerations

HIV/AIDS

Ocular involvement may be the first manifestation of systemic disease. Patients with CD4 counts below 200 cells/μL are particularly vulnerable.¹¹

Post-transplant patients

Patients on tacrolimus or mycophenolate mofetil have an increased risk of viral and fungal keratoconjunctivitis. Prophylactic therapy and regular monitoring are recommended.¹²

Pediatric population

Immunocompromised children, especially those undergoing chemotherapy, may not verbalise symptoms effectively. High vigilance by caregivers and clinicians is essential.

Prognosis

The outcome of keratoconjunctivitis in immunocompromised patients depends on:

• Early detection and appropriate treatment
• Severity of immunosuppression
• Type of pathogen involved

Delayed diagnosis or inadequate therapy can lead to complications such as corneal perforation, endophthalmitis, and irreversible vision loss.

Conclusion

Keratoconjunctivitis in immunocompromised individuals is a serious condition with diverse etiologies and potential for severe outcomes. A thorough understanding of risk factors, vigilant screening, prompt diagnosis, and tailored management are essential for improving patient outcomes. Collaboration between ophthalmologists, infectious disease specialists, and primary care providers is crucial for comprehensive care.