Delusional Parasitosis with Associated Thyroid Abnormality

Delusional parasitosis is a rare, monosymptomatic psychosis involving a delusion of being infested with parasites seen commonly in females. It is classified as a delusional disorder according to the 10th revision of the International Classification of Diseases and as a delusional disorder - somatic type according to the Diagnostic and Statistical Manual, Fourth Edition. We present this rare case of delusional parasitosis in an elderly female with her symptoms paralleling her thyroid profile. Case presentation Our patient was a 68-year-old, South Indian woman with primary school education who had been living alone for the past twenty years. She presented to our out patient department complaining of multiple worms on her body. However, on examination, no worms or skin disease was evident. She was also diagnosed with hyperthyroidism, with exacerbation of delusions with increased thyroid hormones ad vice versa. She was treated with antithyroid medication and with pimozide 2mg/day for 10 months and followed-up without any antipsychotic treatment for an additional five months. At her last examination, she was euthyroid, not receiving antipsychotics and was not having any delusions. Conclusion Rarely, few endocrine conditions like hyperthyroidism can cause secondary delusional parasitosis. This case demonstrated a rare occurrence of correlation of symptoms with her thyroid profile.