Mucus Fishing Syndrome

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Article initiated by:

Nikolas Hopkins

All contributors:

Andrew Go Lee, MD, Caitlin Makenzie Hackl, Sanjana Jaiswal, Nagham Al-Zubidi, MD, Elizabeth Arogundade, Sanjana Jaiswal, Colleen Halfpenny, M.D., Michael T Yen, MD

Assigned editor:

Maria D. Bernal, MD, Kelvin Chong, MB ChB FHKAM(Ophth)

Review:

Assigned status Up to Date

 by Michael T Yen, MD on December 2, 2024.

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Disease

Mucus fishing syndrome is an inflammatory disorder of the conjunctival epithelium caused by repetitive self-induced mechanical trauma. This condition often arises secondary to other disorders that lead to ocular irritation and increased mucus production, such as allergic conjunctivitis, bacterial conjunctivitis, blepharitis, and keratoconjunctivitis sicca. The syndrome develops when patients repeatedly remove or “fish” mucus from the conjunctival cul-de-sac, resulting in chronic papillary conjunctivitis. The mechanical trauma caused by this removal leads to increased mucus production, perpetuating a cycle of further trauma as patients attempt to extract the mucus. Mucus fishing syndrome was first described in 1985 and was named for the characteristic behavior of extracting or “fishing” mucus from the eye observed in affected patients.

Risk Factors

Risk factors for Mucus fishing syndrome include allergic conjunctivitis, bacterial conjunctivitis, blepharitis, keratoconjunctivitis sicca, floppy eyelid syndrome, pterygium, squamous cell carcinoma of the conjunctiva, and exposure keratoconjunctivitis. These conditions can lead to increased mucus production, triggering the cascade of removal, trauma, and further mucus production.

Pathophysiology

In mucus fishing syndrome, mechanical trauma stimulates goblet cells within the conjunctiva to increase mucus production, initiating a cyclic cascade of trauma and mucus overproduction, which further drives the impulse for manual extraction. Additionally, digital manipulation introduces irritants to the ocular surface, leading to complement activation, mast cell degranulation, and histamine secretion.

Primary prevention

Prevention of mucus fishing syndrome involves treating underlying external ocular conditions. Educating patients on the importance of avoiding repetitive digital trauma to the conjunctiva is also crucial in preventing the initiation of the cycle of trauma and increased mucus production.

Diagnosis

Mucus fishing syndrome is often diagnosed through a detailed patient history that reveals the compulsive extraction of mucus strands from the eye. The diagnostic accuracy based on history alone is reported to be as high as 88%. In cases where the patient is unaware of the behavior, input from family members can assist in the diagnosis. Additional diagnostic workup may include staining with rose bengal or fluorescein to identify areas of irritation and conjunctival epithelial defects, which are most commonly asymmetric and located in the inferior cul-de-sac.

History and Symptoms

Patients may present with ocular redness, foreign body sensation, conjunctival irritation, tearing, blurry vision, and excess mucus. A history of treated or untreated external ocular disease, which initially caused a foreign body sensation and led to digital manipulation of the tarsal conjunctiva, is often reported. Due to the nonspecific nature of these symptoms, the syndrome may be misdiagnosed or overlooked, resulting in persistent inflammation.

Physical examination

Staining with rose bengal or fluorescein may reveal well-circumscribed tarsal conjunctival defects and mucus strands. Additionally, patients may exhibit mild to severe injection of the tarsal and bulbar conjunctiva.

Differential diagnosis

• Allergic conjunctivitis
• Bacterial conjunctivitis
• Keratoconjunctivitis sicca
• Blepharitis
• Ocular Munchausen Syndrome

Management

The cornerstone of treating Mucus fishing syndrome is preventing patients from manually extracting mucus to avoid ongoing ocular surface inflammation. If mucus removal is necessary, patients should be advised to avoid touching the conjunctival surface during the process. Eliminating the stimulus for mucus extraction may be achieved pharmacologically with mucolytic agents and antihistamines. Additionally, antibiotics may be prescribed to prevent secondary bacterial infection, and corticosteroids may be used to reduce inflammation.

It is also essential to treat any underlying conditions, such as blepharitis or bacterial conjunctivitis, that contribute to ocular irritation and mucus production.

Prognosis

With the avoidance of digital trauma and appropriate medical treatment, mucus fishing syndrome has a favorable prognosis, with most cases resolving completely. This is evidenced by a reduction in rose bengal or fluorescein staining, indicating improved ocular surface integrity. However, due to the impulsive nature of mucus removal, patients must develop psychological tolerance to the discomfort that may occur during recovery.