Phlyctenular keratoconjunctivitis is a delayed hypersensitivity reaction induced by microbial proteins. Common causative microorganisms include Mycobacterium tuberculosis, Staphylococcus aureus, Candida albicans, Coccidioides spp., and Chlamydia trachomatis.
Clinical Manifestations
The condition occurs more frequently in females, adolescents, and children, with a higher incidence during spring and summer. Mild foreign body sensation is often present, while symptoms tend to worsen when the cornea is involved. Phlyctenular conjunctivitis initially presents as solid, raised, red lesions measuring 1–3 mm, surrounded by a congested area. Lesions at the limbus often form triangular shapes pointing toward the cornea, with the apex prone to ulceration. These ulcers usually heal within 10–12 days without leaving scars. When the lesions occur at the limbus, they appear as single or multiple small grayish nodules, which are smaller than those in phlyctenular conjunctivitis. Congestion surrounding the lesion is observed, and mild scars can remain after healing, resulting in an irregular, serrated limbal contour. Symptoms of primary phlyctenular conjunctivitis may subside but recur when triggers such as active blepharitis or acute bacterial conjunctivitis are present. Recurrent episodes may lead to the progression of lesions toward the central cornea, accompanied by the development of neovascularization, a condition referred to as fascicular keratitis. Post-healing, band-like opacities may remain, while the blood vessels gradually atrophy. In rare cases, the lesions may occur on the cornea or the tarsal conjunctiva.
Diagnosis
Diagnosis can be confirmed based on the presence of characteristic solid, nodular lesions at the corneal limbus or bulbar conjunctiva, accompanied by surrounding congestion and related symptoms.
Treatment
Underlying diseases that trigger this condition should be addressed. Local corticosteroid eye drops are effective, particularly in phlyctenular conjunctivitis caused by tuberculin protein, which responds well to steroids. Major symptoms show improvement within 24 hours of corticosteroid application, and complete resolution of lesions is observed within another 24 hours. Cases involving bacterial infections of adjacent tissues require antibiotic treatment. Nutritional supplementation, including various vitamins, is beneficial for improving general health and enhancing physical resilience. For patients with recurrent fascicular keratitis and corneal scarring leading to significant vision decline, corneal transplantation may be considered as a treatment option.