Table 3.

Serpiginous choroiditis: proposed etiologies.

Proposed etiology	In favor	Against
Autoimmune	Negative infectious disease work up in most patients with typical presentation of the disease Association with HLA-B7 and -A2 Association with HLA-B8 and -Dw3 Favorable control of inflammation with immunosuppression Anecdotal association with autoimmune disease (celiac disease, Crohn’s disease, polyarthritis nodosa, autoimmune thrombotic thrombocytopenic purpura) Histopathology reports	Only a few patients show systemic autoimmune disease
Infection
Bacterial
Tuberculosis	Serpiginous-like lesions in patients with latent systemic tuberculosis Serpiginous-like feature in patients with PCR evidence for mycobacterium tuberculosis	Clinical features of the typical SC differs from tuberculosis-related multifocal serpiginoid choroiditis/serpiginous-like lesions; the latter presents with multifocal choroidal lesions Vitritis and in some patients, anterior chamber reaction Standard immunosuppressive treatment does not lead to manifest systemic tuberculosis Response to immunosuppressive agents and absence of response to anti-tuberculosis agents
Syphilis	Syphilis could present with any chorioretinitis feature Serpiginous-like choroiditis lesions reported in patients with syphilis	Syphilis serology is negative in all typical cases of SC
Viral
Varicella zoster or Herpes simplex	Serpiginous choroiditis reported in patients with herpes zoster ophthalmicus PCR-proven presence of herpes zoster or herpes simplex virus DNA in aqueous humor samples from patients with multifocal serpiginous-like choroiditis	Diagnostic work up for the viral infection is negative in typical patients Serpiginous choroiditis does not respond to antiviral agents Standard immunosuppressive treatment is usually sufficient to control the inflammation
vascular	Elevated factor VIII/von Willebrand factor	Other diseases with elevated factor VIII/von Willebrand factor level do not show serpiginous choroiditis features
Degenerative/dystrophy	Chronic and progressive course Occurrence in middle age	SC is an inflammatory condition treatment consists of immunosuppression

PCR= polymerase chain reaction; RPE= retinal pigment epithelium; SC= serpiginous choroiditis