Follicular Conjunctivitis

This photo shows an excellent example of follicular conjunctivitis. This individual presented with a recent history of unilateral ocular irritation and injection that eventually became bilateral. He complained of mild photophobia and discomfort. Palpation of his preauricular nodes revealed moderate tenderness. In addition to the obvious follicular changes, he had grade 1 corneal fluorescein staining. Our initial diagnosis was bilateral follicular conjunctivitis.

Follicles are multilayer structures; the corona (outer layer) is composed of plasma cells and mature lymphocytes, the stroma (central layer) is composed of lymphocytes and plasma cells, and the germinal center (innermost layer) is composed of immature lymphocytes.1 Follicular conjunctivitis may be classified as acute or chronic.1

Numerous underlying conditions may present as follicular conjunctivitis; the following table is modified from Ophthalmology Review (2016)1

Ocular Infection Systemic Infection Medications
Acute hemorrhagic conjunctivitis
Chlamydia – sexually transmitted disease
Chlamydia- zoonosis: sheep, goats, cats, koalas
Herpes simplex virus
Molluscum contagiosum (may be unilateral presentation)
Lyme disease (stage 1)
Newcastle’s disease
Pharyngoconjunctival fever2
Sulfa antibiotics

The workup and management of follicular conjunctivitis begin with a thorough history. Chronicity, or poor response to treatment, is an important indicator that the underlying disease process may be more than a viral infection. Duncan et al reported a case of chronic follicular conjunctivitis that failed to respond to conventional therapy.4

Additional evaluation including histopathologic testing revealed bilateral low-grade conjunctival lymphoma. The patient responded well to radiation therapy.

One special case of follicular conjunctivitis that bears mentioning is chronic follicular conjunctivitis in humans, particularly children, associated with close contact with cats. Halánová et al evaluated the prevalence of Chlamydia felis in cats and found that the positivity was 35.7% in stray cats, 31% in shelter cats, and 10% in pets who were allowed to free-roam outside. In evaluation of a patient who had longstanding, chronic follicular conjunctivitis, it would be helpful to know whether he or she has a free-roaming cat and whether the cat sleeps with the owner.


  1. Follicular Conjunctivitis. Ophthalmology Review. 2016 Mar 15. Available at . Accessed April 30, 2020.
  2. Chigbu DI, Labib A. Pathogenesis and management of adenoviral keratoconjunctivitis. Infect Drug Resist. 2018 Jul 17;11:981-983.
  3. Shen E, Kate Xie K, Jwo K et al. Dupilumab-Induced follicular conjunctivitis. Ocul Immunol Inflamm. 2019 Aug;27:1339-1341.
  4. Duncan J, Chen Y, Fuchs D, Cantu C, Wang M. Follicular Lymphoma Presenting Solely as Chronic Follicular Conjunctivitis. Cornea. 2016 Mar;35:395-398.
  5. Halánová M, Petrová L, Halán M, Trbolová A, Babinská I, Weissová T. Impact of way of life and environment on the prevalence of Chlamydia felis in cats as potentional sources of infection for humans. Ann Agric Environ Med. 2019 Jun;26:222-226.