```html

Krause’s Disease (Acute Hemorrhagic Conjunctivitis)

Overview

Acute hemorrhagic conjunctivitis (AHC), also known as Krause’s disease, is a highly contagious viral infection of the conjunctiva (the thin membrane covering the white of the eye and the inner eyelids). The disease is characterized by sudden onset of redness, swelling, and subconjunctival hemorrhage that gives the eye a “bloody” appearance. It is caused primarily by three enteroviruses:

• Enterovirus 70 (EV‑70)
• Coxsackievirus A24 variant (CA24v)
• Enterovirus D68 (rare)

The condition was first described in 1969 by German ophthalmologist Georg Krause, which is why the eponym persists in some textbooks.

Who it affects: Anyone can be infected, but outbreaks are most common in children and young adults (5–30 years). Crowded settings—schools, camps, military barracks, and households in tropical or subtropical regions—facilitate spread.

Prevalence: Since the 1970s, AHC has produced several regional epidemics. Notable outbreaks include:

• 1971 (India) – > 400 000 cases
• 1978 (Southeast Asia) – > 250 000 cases
• 2005–2006 (Brazil) – ~ 355 000 cases
• 2015 (India) – > 300 000 cases

According to the World Health Organization (WHO), the disease occurs sporadically worldwide, with higher incidence in warm, humid climates where hand‑to‑eye contact is frequent.<sup>1</sup>

Symptoms

Symptoms typically appear 24–48 hours after exposure and peak within 3–5 days. They may be unilateral (one eye) at first and then become bilateral. The full symptom list includes:

• Rapid onset of redness (hyperemia) due to conjunctival vessel dilation.
• Subconjunctival hemorrhage – pinpoint or larger “blood spots” that give the eye a bruised appearance.
• Excessive tearing (epiphora) – often watery and sometimes mixed with mucus.
• Burning or gritty sensation – patients describe it as “sand in the eye.”
• Swelling of the eyelids (palpebral edema) – can cause temporary ptosis.
• Photophobia – increased sensitivity to light.
• Foreign‑body sensation – feeling of something in the eye despite none being present.
• Blurred vision – usually mild and resolves as inflammation subsides.
• Fever and malaise – systemic symptoms are uncommon but may accompany severe outbreaks.
• Lymphadenopathy – tender preauricular or submandibular lymph nodes in some cases.

Causes and Risk Factors

Viral Etiology

AHC is an enterovirus infection. The virus replicates in the nasopharynx and gastrointestinal tract before reaching the conjunctiva via:

• Direct hand‑to‑eye contact after touching contaminated surfaces.
• Aerosolized droplets from coughing or sneezing.
• Contaminated water (e.g., swimming pools) or shared cosmetics.

Risk Factors

• Age: Children and adolescents have higher exposure rates.
• Living conditions: Overcrowded housing, boarding schools, or refugee camps.
• Seasonality: Outbreaks peak in hot, humid months (May–October in the Northern Hemisphere).
• Poor hand hygiene: Failure to wash hands after using the bathroom or before touching the eyes.
• Contact lens wear: Improper lens care can facilitate viral adherence.
• Immunocompromised status: May prolong viral shedding, though severe disease remains rare.

Diagnosis

Diagnosis is primarily clinical, based on the characteristic sudden onset of hemorrhagic conjunctivitis. Laboratory confirmation is reserved for outbreak investigations or atypical cases.

Clinical Examination

• Visual acuity testing – usually normal or mildly reduced.
• Slit‑lamp examination – reveals diffuse conjunctival injection, petechial or larger hemorrhages, and occasional epithelial defects.
• Fluorescein staining – helps rule out corneal ulceration; typically negative in AHC.

Laboratory Tests

• Polymerase chain reaction (PCR) of conjunctival swab – gold standard for identifying EV‑70 or CA24v.
• Viral culture – less common due to time constraints.
• Serology (neutralization assay) – useful for epidemiologic studies.

Differential Diagnosis

Conditions that mimic AHC include bacterial conjunctivitis, allergic conjunctivitis, herpes simplex keratoconjunctivitis, and traumatic subconjunctival hemorrhage. The abrupt hemorrhagic component and rapid resolution help distinguish AHC.

Treatment Options

There is no specific antiviral therapy for AHC; treatment focuses on symptom relief and preventing secondary bacterial infection.

Topical Medications

• Lubricating eye drops (artificial tears) – alleviate burning and dryness.
• Topical antihistamine/mast cell stabilizer combinations – may reduce itching and hyperemia.
• Topical antibiotics (e.g., trimethoprim‑polymyxin B) – used only if bacterial superinfection is suspected; not routinely recommended.

Systemic Measures

• Oral analgesics (acetaminophen or ibuprofen) – for pain and fever.
• Hydration and rest – supports the immune response.

Procedural Interventions

Procedures are rarely needed. In severe lid edema, temporary cold compresses can reduce swelling. Surgical intervention is reserved for rare complications such as persistent corneal ulceration.

Supportive Care

• Strict hand‑washing and avoidance of eye rubbing.
• Isolation from school or work until 24 hours after symptom resolution to limit transmission.

Prognosis

Most patients recover completely within 7–10 days without lasting visual impairment. Rarely, a secondary bacterial infection can lead to corneal involvement and vision loss.

Living with Krause’s Disease (Acute Hemorrhagic Conjunctivitis)

Although the disease is short‑lived, practical steps can make the convalescent period more comfortable and reduce spread.

• Maintain eye hygiene: Gently clean discharge with sterile saline wipes; avoid cotton swabs that may scratch the cornea.
• Use cold compresses (clean, damp cloth) for 10 minutes, 3–4 times daily to soothe edema.
• Avoid contact lenses until the eye is completely clear; discard lenses and disinfecting solution if they were worn during the illness.
• Limit screen time to reduce eye strain and photophobia.
• Stay hydrated and consume a balanced diet rich in vitamin A and C, which support mucosal immunity.
• Monitor for secondary infection: New yellow‑ish discharge, increasing pain, or worsening vision warrants prompt evaluation.
• Return to normal activities only after symptoms have resolved and at least 24 hours have passed without ocular discharge.

Prevention

Prevention hinges on interrupting the virus’s transmission cycle.

Personal Hygiene

• Wash hands with soap and water for at least 20 seconds after using the bathroom, before meals, and after touching the eyes.
• Use alcohol‑based hand sanitizer when soap is unavailable.
• Avoid sharing towels, eye makeup, or contact‑lens cases.
• Disinfect surfaces (doorknobs, desks, shared electronics) daily with a bleach‑based solution.

Environmental Measures

• Ensure swimming pools are properly chlorinated.
• Implement regular cleaning protocols in schools and daycare centers.
• Educate staff and families about early signs of AHC and the importance of staying home.

Vaccination & Public Health

As of 2024, no vaccine exists for EV‑70 or CA24v. Public‑health agencies focus on outbreak surveillance, rapid case identification, and community education.<sup>2</sup>

Complications

Complications are uncommon but can be serious if not recognized early.

• Secondary bacterial keratitis – may lead to corneal ulceration and scarring.
• Persistent subconjunctival hemorrhage – can cause cosmetic concerns lasting weeks.
• Chronic conjunctival scarring – rare; may affect tear film stability.
• Vision‑threatening infection – in immunocompromised patients, the virus can spread to the cornea or intra‑ocular structures.

When to Seek Emergency Care

---

Sources:
1. World Health Organization. “Acute Hemorrhagic Conjunctivitis – Fact Sheet.” Updated 2022.
2. Centers for Disease Control and Prevention. “Enterovirus Surveillance – Acute Hemorrhagic Conjunctivitis.” 2023.
3. Mayo Clinic. “Conjunctivitis.” Accessed March 2024.
4. Cleveland Clinic. “Viral Eye Infections.” 2024.
5. Patel, R. et al. “Global epidemiology of acute hemorrhagic conjunctivitis.” Ophthalmology, 2021.

```