History: Pyoderma gangrenosum (PG) was first described in 1930. It is an uncommon condition of unknown etiology characterised by an erythematous pustule or nodule progressing to become a necrotic ulcer with an undermined and violaceous edge. It commonly involves the lower extremities and trunk but less commonly head and neck. Pathergy is a characteristic feature of PG. In 50 % of cases, PG is associated with systemic diseases such as inflammatory bowel disease, hepatitis, or myeloproliferative disorders.