Contiguous inflammation of the skin (CIS) is a condition comprising localized inflammatory skin reactions which are secondary to a source of infection originating in deeper anatomical structures (bacterial or sterile abscesses, neoplasm-associated inflammations, foreign bodies, osteomyelitis, sinusitis, etc.). The main clinical symptom of contiguous inflammation of the skin is an asymmetrical, localized and painful erythema in combination with different case-specific symptoms. Four patients are presented below, who developed CIS caused by an ethmoidal carcinoma with superinfection, a postoperative mediastinal abscess, an odontogenic staphylococcal abscess and a purulent sinusitis maxillaris. The purpose of this paper is to bring attention to this condition and to offer guidelines for a rapid diagnosis of its underlying, potentially life-threatening, causal inflammatory focus.