Postherpetic Neuralgia Presenting as Delusional Parasitosis: A Case Series.

Delusional parasitosis (DP) or Ekbom's disease is a rare psychiatric condition where the sufferers have a firm-fixed belief of insects crawling over their skin. The condition may be primary monosymptomatic hypochrondrical delusion or secondary to an underlying psychiatric or organic condition. We present two cases of elderly men presenting with classical symptomatology of DP, which is found to be secondary to postherpetic neuralgia following an acute episode of shingles or herpes zoster infection. One patient responded to a combination of antipsychotic, olanzapine, and pregabalin, used for neuropathic pain, and the other patient responded completely with medications used for neuropathic pain only without any antipsychotic use.