(See also Introduction to Corneal Disorders.)
Phlyctenular keratoconjunctivitis results from a hypersensitivity reaction to bacterial antigens, primarily staphylococcal, but tuberculosis (TB), Chlamydia, and other agents have been implicated. It is more common among children. Many patients also have blepharitis.
Patients have multiple lesions, consisting of small yellow-gray nodules (phlyctenules) that appear at the limbus, on the cornea, or on the bulbar conjunctiva and persist from several days to 2 weeks. On the conjunctiva, these nodules ulcerate but heal without a scar. When the cornea is affected, severe lacrimation, photophobia, blurred vision, aching, and foreign body sensation may be prominent. Frequent recurrence, especially with secondary infection, may lead to corneal opacity and neovascularization with loss of visual acuity.
Diagnosis is by characteristic clinical appearance. Testing for TB may be indicated (eg, for patients at risk).
Treatment for nontuberculous cases is with a topical corticosteroid–antibiotic combination. If patients have seborrheic blepharitis, eyelid scrubs may help prevent recurrence.