• Uncommon, usually unilateral, affects conjunctiva and/or cornea
• Seen more commonly in children and young adults
• Due to type IV hypersensitivity reaction to microbial agents
• Pinkish-white nodule at limbus involving conjunctiva and/or cornea
Treat blepharitis: lid scrubs
Delayed type hypersensitivity to bacterial antigen
• Staphylococcal infection
• Chlamydia, Candida, Coccidioides
COMMONLY ASSOCIATED CONDITIONS
• Pain, photophobia, tearing, foreign body sensation, redness
– If cornea involved, symptoms more severe
• Conjunctival phlycten: small, round, elevated, yellow to white nodule near limbus
• Corneal phlycten: starts at limbus, can extend onto cornea, may have associated epithelial defect
DIAGNOSTIC TESTS & INTERPRETATION
Chest X-ray (CXR), purified protein derivative (PPD) if suspicious of tuberculosis (1)[C]
CXR, PPD in suspicious cases
Corneal cultures if infectious keratitis suspected (1)[C]
Histopathology shows that nodules are composed of lymphocytes, histiocytes, and plasma cells.
• Rosacea keratitis
• Inflamed pinguecula
• Limbal herpes keratitis
• Microbial keratitis
• Nodular episcleritis
Treat underlying blepharitis: lid scrubs, artificial tears, antibiotic ointment (erythromycin or bacitracin) 4 times a day
• Short course of topical steroid–antibiotic combination 4–6 times a day
• Systemic tetracycline 250 mg q.i.d. for 2–4 weeks (2)[C]
• Topical metronidazole
• Topical antibiotics if bacterial keratitis suspected
Side effects of long-term topical steroid use include cataract formation and glaucoma.
Tetracycline contraindicated in children. Substitute erythromycin 250 mg q.i.d.
• Tetracycline contraindicated in pregnant or nursing women. Substitute erythromycin 250 mg q.i.d.
• Steroids are class C and of unknown safety in lactation.
Issues for Referral
Recurrent or causing corneal scarring
• Mild cases will resolve in 2–4 weeks.
• Follow patient weekly.
If cornea involved, monitor for scarring or epithelial defect leading to melting.
Long-term treatment of blepharitis with lid scrubs, artificial tears, and ointment to prevent recurrence
Overall good; if severe, may have residual corneal scarring leading to decreased vision.
Corneal scarring, decreased vision
1. Robin JB, Schanzin DJ, Verity SM, et al. Peripheral cornea disorders. Surv Ophthalmol 1986;31:1–36.
2. Abu el-Asrar AM, Tabbara KF. Tetracycline treatment of phlyctenulosis. Ophthalmology 1994;101:1161–1162.