A rare case of brucellosis with dermatomal pattern of cutaneous manifestation.

Brucellosis is a systemic disease which may involve any organ or system of the body, and is listed in the differential diagnosis of many diseases. In spite of described cutaneous involvements, skin manifestations are not common in brucellosis, particularly papulonodular lesions with dermatomal patterns that may overlap with dermatomal skin lesions. This may prevent correct diagnosis and treatment in practice, harming patients' health and leading to financial costs to the health system and patient. In this case, at first, due to left thigh and buttock skin lesions and dermatomal pattern, the patient was diagnosed with infection. After medical treatment and no improvement of lesions, the patient was referred to the infectious clinic with low back pain; magnetic resonance imaging (ordered by a neurosurgeon) suggested infectious spondylodiscitis. At the infectious ward, brucellosis spondylitis was diagnosed and a biopsy was taken from dermatomal lesions. The patient's follow-up after 1, 2, and 3 months revealed that treatment of brucellosis had led to healing of lesions. Surprisingly, the histopathological assessment of the biopsy suggested psoriasis vulgaris. This was a rare case of manifestation of cutaneous brucellosis which could not even be diagnosed by histopathological assessment.