Herpes zoster is a frequent painful
infectious disease whose incidence and severity increase with age. In older people, there is a strong bidirectional link between
herpes zoster and functional decline, which refers to a decrement in ability to perform
activities of daily living due to ageing and disabilities. However, the exact nature of such link remains poorly established. Based on the opinion from a multidisciplinary group of experts, we here propose a new model to account for the interplay between
infection, somatic/psychiatric comorbidity, coping skills,
polypharmacy, and age, which may account for the functional decline related to
herpes zoster in older patients. This model integrates the risk of decompensation of underlying disease; the risk of
pain becoming chronic (e.g.
postherpetic neuralgia); the risk of
herpes zoster non-
pain complications; the detrimental impact of
herpes zoster on quality of life, functioning, and mood; the therapeutic difficulties due to multimorbidity,
polypharmacy, and ageing; and the role of stressful life events in the
infection itself and comorbid depression. This model underlines the importance of early treatment, strengthening coping, and
vaccine prevention.