Otitis externa, green nail syndrome, toe web infections, hot tub folliculitis, superinfections in chronic antibiotic-treated acne and infectious eczematoid dermatitis are examples of mild cutaneous infections due to Pseudomonas aeruginosa. These may occur in otherwise healthy persons. In persons with lowered resistance, more severe infections such as malignant otitis externa, blastomycosis-like pyoderma and necrotizing fasciitis are observed. Ecthyma gangrenosum, the pathognomonic skin sign of Pseudomonas septicemia, occurs in debilitated or terminally ill patients and must be treated immediately.