Phlyctenule

Associated toxic epithelial keratitis should respond to blepharitis treatment. Topical steroids are generally not required imless the cornea is significantly involved or a phlyctenule is present. In this case prednisolone 0.12% used two or three times a day for a few days may be used. Combination steroid-antibiotic ointments, such as tobramycin-dexamethasone or the topical combination drop tobramycin-loteprednol, may prove to be useful for those patients complaining of excessive itching and burning. Steroids control the hypersensitivity component that is often present and reduce the congestion and irritation that often provoke the patient to rub the eye and aggravate the blepharitis. 

If a significant inflammatory component or a response to bacterial exotoxin hypersensitivity in the fiarm of marginal corneal infiltrates or phlyctenules is present, treatment may require concurrent topical steroid therapy. When chronic dacryocystitis is involved, treatment should include irrigation of the lacrimal system with trimethoprim-polymyxin B or gentamicin. Adjunctive systemic antibiotic therapy may also be required (see Chapter 24). 

Figure 25-32 Conjunctival phlyctenule arrow ) in inter-palpebral aperture. (Courtesy William Wallace, O.D.)...

A phlyctenule is a focal nodule composed of leukocytes, generally the result of a delayed hypersensitivity reaction to microbes or their toxins. For this antigenic response to occur, the patient must have a history of previous exposure and sensitization to the causative organism... 

Tuberculosis has reemerged in the United States among recent immigrants and patients with acquired immime deficiency syndrome. It has been suggested that hypersensitivity to tuberculoprotein has a role in the development of phlyctenules. Considering the ease of air travel and the feet that approximately one-third of the world s population has been infected with tuberculosis, the possibility of tuberculosis exists in every patient with phlyctenulosis. Many patients who exhibit phlyctenulosis also have a high rate of positive skin and radiology tests for tuberculosis. It is not uncommon for patients with phlyctenulosis to relate a history of recent exposure to, or femily members with, known tuberculosis. 

Slit-lamp examination reveals single or multiple phlyctenules that appear as pinkish white nodules on the cornea or conjunctiva, ranging in size from just visible to several millimeters in diameter.They typically appear first at the limbus and can easily be mistaken for catarrhal ulcers. Unlike catarrhal ulcers, phlyctenules are adjacent to the limbus, and the long axis of a phlyctenule is perpendicular to the limbus rather than parallel to it. 

Along with the phlyctenule, examination often reveals conjunctival hyperemia, a scanty watery discharge, and diffuse corneal staining. If the phlyctenule is caused by Staphylococcus, an associated blepharitis is common. Phlyctenules typically last from 10 to 14 days and occur primarily in children, with girls more frequently affected than boys. 

Conjimctival phlyctenules appear on the limbus or bulbar conjimctiva. Lesions are usually close to the limbus near the free lid margin but can present anywhere on the bulbar conjimctiva. They rarely affect the palpebral conjunctiva. They often are surrounded by hyperemia. Corneal phlyctenules typically start at the limbus and are accompanied by a leash of conjunctival vessels (Figure 26-41). Initially, the overlying epithelium is intact... 

Figure 26-41 (A) Corneal phlyctenule accompanied by a leash of conjunctival vessels. (B) Corneal phlyctenule. (Courtesy of Pat Caroline.)...

The vessels associated with the phlyctenule also migrate toward the center of the cornea and produce focal neovascularization. Triangular corneal scars with their base at the limbus often form as phlyctenules heal. These scars can be vascularized. Scarring in the central cornea can decrease visual acuity if the phlyctenulosis is long-standing. Corneal perforation in phlyctenulosis is rare but has been reported. 

Although phlyctenules can resolve spontaneously, they usually ulcerate and scar before resolution. To prevent scarring, treatment should include 1% prednisolone acetate, one drop every 2 to 4 hours for 3 to 4 days. Also, instill prophylactic antibiotic ointment or drops, such as bacitracin, erythromycin, or polymyxin B/trimethoprim, into the conjunctival sac four times a day and continue as... 

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