Blastomycosis-like Pyoderma Arising in Lichen Planus.

Blastomycosis-like pyoderma (BLP) is a rare reactive skin disease that is most commonly caused by bacterial infection. Herein we present a case of BLP arising in lichen planus, a chronic inflammatory disease. We propose Wolf's isotopic response, or the appearance of a new skin disease at the site of an existing and unrelated disease, as the underlying molecular mechanism responsible for this unusual physical presentation. It is important that clinicians recognize atypical morphologies such as BLP, which mimics squamous cell carcinoma both clinically and pathologically. These similarities highlight the need for a tissue diagnosis to identify infectious etiologies and rule out malignancy when BLP is suspected. J Drugs Dermatol. 2018;17(2):233-235.