A viral etiology of sudden hearing loss has been hypothesized by many authors. HSV1 neurotropism and its involvement in sudden hearing loss has implicated HSV1 as one of the most accredited etiological agents. A non-invasive method such as the titration of HSV1-specific IgA was evaluated to determine the role of HSV1 as a possible cause sudden hearing loss. A prospective study was carried out by titration of serum IgA to HSV1 in 93 patients and in a control group of 50 healthy subjects and 35 subjects suffering from recent herpes labialis reactivation. Statistical analysis of the results disclosed that IgA titers to HSV1 higher than 1:80 are suggestive for the association of HSV1 infection and sudden hearing loss. Moreover, acyclovir therapy was effective in 81% of patients who showed high specific IgA titers. Overall, the titration of specific serum IgA to HSV1 can be a useful tool to determine the viral etiology of certain cases of sudden hearing loss. This method is simple to perform and minimally invasive. It can lead to a rapid presumptive diagnosis and to prompt specific therapy, reducing the need for corticosteroids.