The most common cause of the development of odontogenic infection is untreated dental caries, which initially leads to pulpitis. If an odontogenic infection is left untreated, it will pass through the limiting bone plate and will infiltrate deeper structures. Odontogenic infections are different in adults and children. The study was conducted at the Department of Pediatric Otolaryngology and Pediatric Head and Neck Surgery of Upper Silesian Children’s Health Center in Katowice in the 2020–2022. We included 27 patients aged 2–16 in the study. Patients were diagnosed with an active, acute odontogenic inflammatory process in the head and neck area. We assessed pain, trismus, extraoral and intraoral swelling and the level of CRP [C Reactive Protein], WBC [White Blood Cells], NLR [Neutrophil Lymphocyte Ratio], D-dimers and Prealbumins. The results were analyzed in terms of the location of the source of inflammation: maxilla or mandible and the type of source of infection: deciduous tooth or permanent tooth. Deciduous teeth are more often the cause of odontogenic infection in the maxilla, while permanent teeth in the mandible. Trismus, extraoral, and intraoral swelling occurred in all infections caused by permanent teeth. The CRP and NLR ratio is statistically higher in infection, which originates from permanent teeth. The mean hospitalization time was also longer for infections from permanent teeth 3.42 days than for deciduous teeth 2.2 days. The varied clinical picture of odontogenic infections in children requires periodic analyzes of statistical data related to epidemiology, etiology, and symptomatology in order to update diagnostic and therapeutic procedures.