the inflammation of all layers of the uvea(Iris, ciliary body and choroid). Causes Uveitis is usually an isolated illness, but can be associated with many other medical conditions. In anterior uveitis, no associated condition or syndrome is found in approximately one-half of cases. However, anterior uveitis is often one of the syndromes associated with HLA-B27. Presence of this type of HLA allele has a relative risk of evolving this disease by approximately 15%. The most common form of uveitis is acute anterior uveitis (AAU). It is most commonly associated with HLA-B27, which has important features: HLA-B27 AAU can be associated with ocular inflammation alone or in association with systemic disease. HLA-B27 AAU has characteristic clinical features including male preponderance, unilateral alternating acute onset, a non-granulomatous appearance, and frequent recurrences, whereas HLA-B27 negative AAU has an equivalent male to female onset, bilateral chronic course, and more frequent granulomatous appearance. Rheumatoid arthritis is not uncommon in Asian countries as a significant association of uveitis. Noninfectious or autoimmune causes Sympathetic ophthalmia Behçet disease Crohn's disease Fuchs heterochromic iridocyclitis Granulomatosis with polyangiitis HLA-B27 related uveitis Spondyloarthritis (especially seen in ankylosing spondylitis) Juvenile idiopathic arthritis Sarcoidosis Tubulointerstitial nephritis and uveitis syndrome Associated with systemic diseases Systemic disorders that can be associated with uveitis include: Enthesitis Ankylosing spondylitis Juvenile rheumatoid arthritis psoriatic arthritis reactive arthritis Behçet's disease inflammatory bowel disease Whipple's disease systemic lupus erythematosus polyarteritis nodosa Kawasaki's disease chronic granulomatous disease sarcoidosis multiple sclerosis Vogt–Koyanagi–Harada disease Infectious causes Uveitis may be an immune response to fight an infection caused by an organism in the eye. They are less common than non-infectious causes, and require antimicrobial/ viral/ parasitic treatment in addition to inflammatory control. Infectious causes in order of global burden include: tuberculosis brucellosis herpesviruses (herpes zoster ophthalmicus - shingles of the eye) leptospirosis presumed ocular histoplasmosis syndrome syphilis toxocariasis toxoplasmic chorioretinitis Lyme disease Zika fever Drug related side effects Rifabutin, a derivative of Rifampin, has been shown to cause uveitis. Several reports suggest the use of quinolones, especially Moxifloxacin, may lead to uveitis. White Dot syndromes Occasionally, uveitis is not associated with a systemic condition: the inflammation is confined to the eye and has unknown cause. In some of these cases, the presentation in the eye is characteristic of a described syndrome, which are called white dot syndromes, and include the following diagnoses: acute posterior multifocal placoid pigment epitheliopathy birdshot chorioretinopathy multifocal choroiditis and panuveitis