Many authors have divided causes of headache into ocular and nonocular causes.9 While majority of these are related to asthenopia or refractive errors, other conditions like corneal ulcers, migraine, glaucoma, giant cell arteritis, idiopathic intracranial hypertension, sinusitis, hypertension and scleritis
are also known to cause headache.10 This shows that all patients with headache must undergo complete ophthalmic evaluation.
The ocular manifestations, such as conjunctivitis, episcleritis, keratitis, scleritis
, uveitis, and retinal vasculitis, can occur in approximately half of the patients.
In addition, extraintestinal effects, such as arthritis, sacroiliitis, primary sclerosing cholangitis, pyoderma gangrenosum, erythematous nodosum, scleritis
, and episcleritis, can be seen.
The risk of cardiovascular death is also associated with the disease activity level, the presence of Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (ACCP) antibodies, disease duration of more than 10 years and presence of extra articular manifestations like rheumatoid nodules, interstitial lung disease, scleritis
, and episcleritis3.
Besides, ocular involvement, such as blepharitis, keratoconjunctivitis, iritis, scleritis
, and acute retinal necrosis, may occur in patients with HZO.
, conjunctivitis, and other pathologic findings in the left eye and brain of an Ebola virus-infected rhesus macaque (Macaca mulatta) with apparent recovery and a delayed time of death.
Optimizing diagnosis and management of Nocardia keratitis, scleritis
, and endophthalmitis: 11-year microbial and clinical overview.
Gaujoux et al., "Scleritis
: a paradoxical effect of etanercept?
proposed the definition of "typical" CS, with the ocular inflammation in addition to cochleovestibular symptoms, and "atypical" CS characterized by (a) ocular lesions other than interstitial keratitis (conjunctivitis, scleritis
, iritis, choroiditis, subconjunctival, or retinal hemorrhage), (b) a delay of more than 2 years from the onset of ocular and cochleovestibular symptoms, and (c) systemic manifestations, including cardiovascular, neurological, and gastrointestinal symptoms .
 reported Aspergillus niger as a cause of endophthalmitis and scleritis
The differential diagnosis includes Stargardt disease, cone dystrophy, enhanced S-cone syndrome, pericentral retinitis pigmentosa, syphilitic placoid chorioretinitis, acute zonal occult outer retinopathy (AZOOR), posterior scleritis
, traumatic retinopathy (commotio retinae), posterior uveitis, hydroxychloroquine toxicity, and autoimmune retinopathy [18-22].
(1) These complications can include blepharitis, keratoconjunctivitis, iritis, scleritis
, and acute retinal necrosis.