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80-Year-Old Female with Eruption on Arms, Chest, and Back

Can you diagnose this case?

David L. Kaplan 2014 Series Editor @ University of Missouri – Kansas City School of Medicine

Signs and Symptoms

An 80-year-old female presented with a several month history of pruritic eruption on her arms, chest, and upper back. She felt like something was crawling under her skin. She brings in material from her house, which she suspects could be the cause.

What could be responsible for her pruritic eruption?

Choose one to reveal diagnosis and discussion

Scabies
Bed bugs
Body lice
Dermatitis herpetiformis
Delusions of parasitosis

Answer: Delusions of parasitosis

See the full case at Consultant360

An extensive and exhaustive workup was unrewarding – suggesting the diagnosis of delusions of parasitosis, which is further supported by the lack of a primary lesion. Patients have no obvious cognitive impairment and abnormal organic factors are absent. True infestations and primary systemic diseases that cause pruritus are not involved. Primary skin lesions are not present. Physical examination may reveal no lesions, but only linear erosions with crusts, prurigo nodularis, and/or ulcers.

Differential Diagnosis: A biopsy will show evidence of insect bite reactions and dermatitis herpetiformis has evidence of pathology on hematoxylin and eosin stain initially before confirmation with immunofluorescence.