Paroxetine is a selective serotonin reuptake inhibitor antidepressant. We present a case of a patient who developed herpes zoster 4 weeks after initiating paroxetine.

A 35 year old female was referred to our hospital due to obsessive compulsive disorder. She complained of intrusive thoughts of being contaminated and repetitive behaviors.

After a thorough laboratory and imaging tests she was prescribed paroxetine 40 miligrams daily.

Four weeks later she complained of pain followed by rash along the same dermatomal distribution in the lower abdominal area. The involved area was tender to palpation.

A detailed dermatologic evaluation was performed and the rash was attributed to herpes zoster. Despite the potential association of paroxetine with herpetic rash the patient continued treatment and was prescribed acyclovir and pain killers. One month later herpetic rash had fully remitted.

This is the first report of herpes zoster attributed to paroxetine therapy. The pathophysiological mechanism governing the effects of SSRIs in immune function is controversial. In vitro studies have shown that SSRIs decreased splenic lymphocyte proliferation while other studies have shown that chronic SSRI treatment is associated with a reduction of the number of leucocytes and neutrophils. It has been suggested that the immune effects of SSRIs are mediated by endogenously released serotonine, while T leymphocytes express 5HT receptors. Although a casual association of herpes zoster and paroxetine therapy cannot be attributed with the described case, further studies are needed to clarify under which circumstances, paroxetine could trigger herpetic rash.