Visual disturbances in dengue fever: an answer at last?

Visual disturbances in dengue infection are uncommon but may result in permanent visual impairment. We report a 32-year-old Chinese woman with dengue infection and she developed retinal haemorrhage, retinal vasculitis and macular detachment. Autoimmune screen revealed a low C4 complement level, possibly due to partial C4 complement deficiency. The patient was treated with steroids and there was significant improvement in her vision. Partial C4 deficiency predisposes to autoimmune disease, and patients with pre-existing low C4 levels may be susceptible to ocular complications in dengue infection. Interestingly, previous case reports of ophthalmic complications of dengue infection occurred in young female patients, who are likewise predisposed to autoimmune disease. In conclusion, in individuals predisposed to autoimmune disease (females and patients with partial C4 deficiency), dengue infection may provide the antigenic trigger for immune complex deposition and retinal vasculitis. Steroids may have an important role in the treatment of this condition.