Ocular Manifestations of Mastocytosis
Mastocytosis affects the eyes primarily through mast cell mediator release causing dry eye disease, ocular itching, and blepharitis in over 80% of patients, with rare but serious orbital infiltration causing exophthalmos and diplopia in systemic disease.
Common Ocular Surface Manifestations
The most frequent ocular effects result from mast cell mediator release rather than direct tissue infiltration:
- Dry eye disease occurs in approximately 52% of mastocytosis patients, often accompanied by superficial punctate keratitis 1
- Ocular itching and dryness are the predominant symptoms, each reported in 57% of patients, with excessive tearing in 43% 1
- Posterior blepharitis affects nearly half of patients (47.6%), contributing to ocular surface inflammation 1
- Moderate to severe ocular surface disease (based on Ocular Surface Disease Index scores) is present in 52.4% of patients 1
These symptoms likely result from histamine and other inflammatory mediators released from activated mast cells, similar to the flushing and pruritus seen in cutaneous manifestations 2.
Rare but Severe Orbital Involvement
In systemic mastocytosis, direct mast cell infiltration can cause dramatic orbital manifestations:
- Bilateral exophthalmos with eyelid edema can occur from mast cell infiltration of extraocular muscles and orbital fat 3
- Diplopia from extraocular muscle involvement, particularly affecting the superior and medial recti muscles and inferior oblique muscle 3
- Histopathological confirmation requires orbital fat and muscle biopsies showing mast cell infiltration 3
- Elevated serum tryptase typically accompanies these severe orbital manifestations, indicating systemic disease burden 3
This represents a rare presentation of systemic mastocytosis, distinct from the more common cutaneous forms that predominate in children 2.
Clinical Recognition and Diagnosis
Look for Darier's sign on skin examination - mild pressure eliciting diffuse erythema strongly suggests mastocytosis and should prompt evaluation for ocular involvement 3.
Key diagnostic considerations:
- Ocular symptoms occur in 81% of mastocytosis patients, making routine ophthalmologic screening reasonable 1
- Tear cytokine levels (IL-1RA, IL-6) do not reliably correlate with ocular symptoms or distinguish mastocytosis patients from controls 1
- Serum tryptase elevation >20 ng/mL suggests systemic disease and warrants more comprehensive evaluation including potential orbital involvement 3, 4
Management Approach
Initiate ocular hydration measures and artificial tears for all mastocytosis patients with eye symptoms, as this addresses the most common manifestation 1.
For symptomatic management:
- H1 and H2 antihistamines serve as the mainstay of therapy to block inflammatory mediator effects 5
- Mast cell stabilizers may reduce mediator release and symptom frequency 2
- Ophthalmologic consultation should be considered for all mastocytosis patients to assess for dry eye disease and blepharitis 1
For severe orbital involvement with exophthalmos:
- Cladribine represents an effective treatment option for orbital mastocytosis, with documented resolution of exophthalmos and eyelid edema persisting 18 months after discontinuation 3
- Bone marrow biopsy is indicated when orbital involvement is suspected to confirm systemic mastocytosis and guide systemic therapy 3
Important Clinical Caveats
Do not dismiss chronic ocular symptoms in patients with unexplained pruritic skin lesions - mastocytosis patients often have prolonged histories of unrecognized symptoms before diagnosis 5.
- Ocular mastocytosis can involve conjunctiva, cornea, uvea, eyelid, orbit, and choroid, though these sites are rarely affected 3
- Avoid triggering factors including temperature extremes, mechanical trauma, and certain medications that can provoke mast cell degranulation and worsen ocular symptoms 2, 6
- Visual acuity typically remains normal even with significant exophthalmos, though diplopia may be functionally limiting 3