Objective: Delusional infestation is a psychiatric condition in which a patient
belief that they are infested with living organisms in the absence of any objective
evidence. The objective of this case report is to highlight a rare case of delusional
infestations in a patient with schizophrenia who misusing polysubstance abuse.
Methods: We report a case of 36-year-old Malay gentlemen, unemployed,
married with three children, known case of schizophrenia since 2013, with
history of polysubstance abuse presented to the emergency department with
symptoms of itching followed by a sensation of insects crawling, biting and
burrowing under the skin on his head causing an ulcerated wound. Results: He
was diagnosed to be suffering from schizophrenia and was successfully treated
with monthly antipsychotic depot injection in view of his poor adherence to
medication On examination, ulcerated scalp wound measuring 4 x 4 cm was
noted at the parieto-occipital region of the scalp. Skull X-ray and computerized
tomography (CT) scan of the brain were normal. Electroconvulsive therapy
(ECT) was introduced in view of slow treatment response and self-inflicted
injury. The symptoms were successfully controlled after eight months, and no
extrapyramidal side effect was observed. Conclusion: Patients with delusional
infestation often poorly adhered to his treatment medication and the usage of
depot injection of antipsychotic may benefited some patients to control the
psychotic symptoms.