Though rare the malignant otitis externa must be borne in mind because in its precocious diagnosis is based the success of the management. Elderly people, diabetics and immunodepressed are especially exposed. The CAT is basic in order to detect the spreading of the process. The patient being admitted at a Medical center, the antibiotherapy started at once with Ceftazidine, 2 g every 12 hours via i.v. The exeresis of the e.e.ca proves sometimes necessary after control of the infection. This procedure assures the healing and prevent the recurrences some times seen. But when infection disappears owing to the success of the antibiotherapy in 2-3 weeks; the culture for Pseudomonas is negative 3 weeks later; and the previous CAT showed no spreading to the tympanal bone, the surgery must be discarded. The process is considered over when the culture for Pseudomonas aeruginosa is negative, but review of the patients is compulsory at least during half a year.