The primary skin lesion usually starts with a macule that is painless, round and erythematous. Then, it develops into a pustule, and then a bulla with central hemorrhagic focus. The bulla progresses into an ulcer which extends laterally. Finally it becomes a gangrenous ulcer with a central black eschar surrounded by an erythematous halo. The lesions may be single or multiple. They are most commonly seen in perineum and under arm pit. However, they can occur in any part of the body.
Ecthyma gangrenosum
Pyoderma gangrenosum
Lichen myxedematosus
Tuberculosis verrucosa cutis
Granuloma faciale
Epidermolysis bullosa
Streptococcal intertrigo
Pseudomonal pyoderma