Skin nodules with a linear distribution - a case study

A man, 35 years of age, with an unremarkable past medical history, attended after developing purplish nodules on the left arm. The nodules were in a linear distribution and had developed during recent months after a minor initial injury. The nodules were moderately painful, but it was mainly the appearance of new nodules that motivated him to consult his general practitioner. On dermatological examination, six purple nodules were observed following a linear distribution along the back of the left hand and arm (Figure 1). They were of variable size. Some of the lesions had a discrete superficial ulceration and a serous crust. The patient had no fever. Small lymph nodes were detected in the left axilla. Systemic examination showed no abnormalities. Laboratory data, including full blood count, general biochemistry and urine analysis were normal. Culture was unremarkable. Histopathologic examination revealed a mixed granulomatous and pyogenic inflammatory process. Cigar shaped organisms were identified by periodic acid-Schiff (PAS) staining.