Cogan syndrome is a rare autoimmune disorder, the etiology of which is obscure. However, the disease shares some clinicopathologic features with polyarteritis nodosa. Progressive ocular and audiovestibular symptoms—which can lead to blindness, deafness, and even death from systemic vasculitits—develop in affected patients.
Cogan syndrome typically occurs in young adults and produces stromal keratitis, vertigo, and hearing loss. The history may reveal a recent upper respiratory tract infection, bout of diarrhea, dental infection, or immunization. The earliest corneal findings are bilateral faint, white subepithelial infiltrates resembling those occurring in viral keratoconjunctivitis but located in the peripheral cornea. Multifocal nodular infiltrates may develop in the posterior cornea later. A systemic vasculitis that presents as polyarteritis nodosa occurs in some patients.
When the cause of stromal keratitis is not apparent, a VDRL or rapid plasma reagin (RPR) test and FTA-ABS or microhemagglutination assay for T pallidum are performed (VDRL and RPR tests may become nonreactive in congenital syphilis). Other infectious syndromes should also be considered. Antibodies to chlamydia have been reported in cases of Cogan syndrome. The presence of autoantibodies against the inner ear and endothelial antigens has been reported in some patients with Cogan syndrome. Hearing testing should be performed when Cogan syndrome is being considered. The erythrocyte sedimentation rate (ESR) and/or the C-reactive protein (CRP) level may be elevated. Fifty percent of patients with Cogan syndrome may test positive for anti–heat shock protein antibodies. Also, case reports have noted that affected patients test positive for antineutrophil cytoplasmic antibody (ANCA), rheumatoid factor (RF), antinuclear antibody (ANA), and anticardiolipin antibodies. However, laboratory findings are not consistent in Cogan syndrome, and there is no definitive test. This syndrome thus remains a diagnosis of exclusion, and it must be considered early on in the differential diagnosis of any patient who has the symptoms and clinical findings mentioned earlier.
Tirelli G, Tomietto P, Quatela E, et al. Sudden hearing loss and Crohn disease: when Cogan syndrome must be suspected. Am J Otolaryngol. 2015;36(4):590–597.
The acute keratitis of Cogan syndrome is treated with frequent topical corticosteroids. Oral corticosteroids are recommended for the vestibular and auditory symptoms because this treatment improves the long-term prognosis. Cytotoxic agents may also have a therapeutic role but are reserved for severe or unresponsive cases. Early recognition and treatment of Cogan syndrome is critical to prevent the rapid progression to vision loss, blindness, deafness, and death from systemic vasculitis. Early consultation with an otolaryngologist and rheumatologist for management is recommended.
Espinoza GM, Prost A. Cogan’s syndrome and other ocular vasculitides. Curr Rheumatol Rep. 2015;17(4):24.
Gluth MB, Baratz KH, Matteson EL, Driscoll CL. Cogan syndrome: a retrospective review of 60 patients throughout a half century. Mayo Clin Proc. 2006;81(4):483–488.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.