- Objective To determine the frequency of mandibular osteomyelitis (OM) in patients with congenital insensitivity to pain with anhidrosis (CIPA) and to relate its appearance to possible risk factors. Methods The records of 33 patients were reviewed for data concerning events of jaw OM, oral trauma, maxillofacial interventions, or OM of long bones. Results Eighteen percent of the patients had mandibular OM. Of the six patients, preceding oral laceration was documented in one and tooth extraction in two. Seventy percent of the patients had OM of the limbs, but only 15% overlapped, having both jaw and limb OM. Half of the patients with mandibular OM had also OM of the limbs during the following year. There seems to be a correlation between high frequency of limb OM (at least 5 events per patient) and appearance of mandibular OM. Conclusion The incidence of mandibular OM is very high among patients with CIPA and can result in pathologic fracture and the need for open reduction and internal fixation. The reason for this phenomenon is presently not clear. Preventive and therapeutic strategy for CIPA patients should be undertaken to minimize this severe complication.