Linear bacterial dissection.

An unusual case of an erythematous indurated arcuate plaque with a curvilinear appearance was noted after a patient manipulated an ingrown beard hair. During removal of a biopsy specimen, a purulent discharge was expressed that had evidently dissected through the dermis forming this interesting shape. This may be similar to a recently reported entity described by Shelley and Shelley as linear bacterial dissection. Culture of the discharge grew Staphylococcus aureus and Klebsiella pneumoniae. Complete resolution occurred after drainage and antibiotic therapy. Cellulitis and erysipelas typically do not show central clearing or form arcuate plaques. Aside from lymphangitis, thrombophlebitis, and sinus tracts of carbuncles, dermal infectious processes rarely present as linear or arcuate plaques. The differential diagnosis and a review of the literature are presented.