Pseudomonas aeruginosa O-11 folliculitis. Development into ecthyma gangrenosum in immunosuppressed patients.

Six immunocompromised patients were shown to exhibit Pseudomonas aeruginosa folliculitis in apocrine regions similar to "swimming pool" folliculitis. The lesions evolved within 24 hours as severe ecthyma gangrenosum. The source of the P aeruginosa, serotype O-11, was found in the water system of the hospital. Clinical identification of the lesions and early treatment is important to prevent severe manifestations.