1)      Crepitus at the site of  cellulitis (clostridia and anaerobic infections, necrotizing fasciitis, anaerobic myonecrosis)

2)      Bullae and/or necrosis of tissues (necrotizing fasciitis, anaerobic myonecrosis)

3)      Gangrene (immuno-compromise, necrotizing fasciitis)

4)      Unusual onsets like – after animal or human bites (cellulitis of unusual organisms), after exposure to seawater, fresh water, muddy water (cellulitis of unusual organisms), illicit drug injection, breast surgery (cellulitis of unusual organisms), CABG, previously injured muscle (anaerobic myonecrosis), vaccination sites (vaccinia vaccination), liposuction (cellulitis of unusual organisms)

5)      Unusual sites like – periorbital, perianal, buccal

6)      High fever and the patient looks ill

7)      Quick progression of symptoms (necrotizing fasciitis)

8)      Involvement of deep tissues (necrotizing fasciitis)

9)      Progressive pain, swelling and tenderness (necrotizing fasciitis)

10)    Immunocompromise (unusual organisms)