Odontogenic Infections with Cutaneous Involvement in Children: a Case Series

Differential diagnosis

Odontogenic infections with cutaneous involvement may present as relatively well localized inflammatory skin lesions, often with purulent collections and discharge. Differential diagnosis may include osteomyelitis, actinomycosis, foreign body, local skin infection, pyogenic granuloma, salivary gland and duct fistulae, cat scratch disease, toxoplasmosis, suppurative lymphadenitis, neoplasm and tuberculosis.^3,4 It is imperative to take a good medical history in order to rule out systemic involvement and aetiology.

Case 1

A 9-year-old girl was referred by her General Dental Practitioner (GDP) for management of her lower right first permanent molar, which was believed to be non-vital. The referral followed a two-year history of pain on the lower left quadrant and subsequent recurrent localized swelling/drainage of pus from an extra-oral sinus, just inside the lower border of the mandible (Figures 1a and 1b). The patient had been seen at multiple centres for investigation and attempted treatment of the extra-oral sinus over a period of 18 months. Therapies included oral and intravenous antibiotics, surgical excision of submandibular lymph nodes, cauterization, biopsies and nine months of tuberculosis therapy following inconclusive investigations (Figure 2). The patient was otherwise fit and well. Initial presentation showed a draining sinus in the anterior left submandibular triangle, erythematous skin, a non-tender nodule with crusting, pus drainage and skin retraction (Figure 3). Intra-orally, the lower left first permanent molar (LL6) was hypomineralized, with a minimal amalgam restoration, no intra-oral swelling or tenderness at percussion. Special investigations included an orthopantomography (OPG) which showed a small radiolucent area on the mesial root of the LL6, inconsistent sensibility testing and normal periodontal charting (Figure 4). Following discussion with maxillofacial surgery and radiology consultants, Cone Beam Computed Tomography (CBCT) was performed, showing a clear sinus tract between the mesial root of the LL6 and the submandibular skin (Figure 5).

Both endodontic treatment and extraction were offered. Owing to the psychological burden of delayed diagnosis and associated aesthetic concerns, both patient and mother refused endodontic treatment in favour of an immediate resolution. The extracted tooth was sent for histopathology, which showed non-vital pulp tissue and fibro-collagenous connective tissue. At one week follow-up, the patient presented with good socket healing and discontinued drainage through the extra-oral sinus. Further reviews indicated continued healing with the patient remaining symptom free (Figure 6). Although there were no concerns with aesthetics then, long-term management was likely to involve scar revision. In this case, inaccurate diagnosis and management led to 18 months of invasive treatment with significant ongoing impact on the child’s physical and psychological health.

Case 2

An 8-year-old boy was referred by his family dentist for management of a right submandibular swelling persisting for 3 weeks, which had failed to respond to a course of oral amoxicillin. The swelling presented with cutaneous involvement, was erythematous, fluctuant, well demarcated and warm at palpation (Figures 7a and b). The patient was apyretic, with no systemic involvement.

An orthopantomograph showed a well-defined, localized, radiolucent area related with the distal root of the right first permanent molar (LR6) (Figure 8).

Following discussion with the maxillofacial team, it was decided to extract the LR6 and prescribe metronidazole. A swab was sent for microbiology and antibiotic resistance tests, showing normal skin microbiology. At 4 days review, the socket was healing well, and the swelling appeared reduced with a localized purulent collection. It was decided to await spontaneous resolution rather than perform extra-oral excision in order to avoid scarring. Further review, five weeks following presentation, showed a reduction of the swelling and resolution of the skin erythema (Figure 9).

Case 3

A 13-year-old girl presented initially with an extra-oral swelling related with her LR6, which had an extensive restoration performed by her GDP. Following discussion of treatment options, the tooth was extirpated and amoxicillin was prescribed (Figure 10). As the swelling persisted two weeks later, an intra-oral incision and drainage were performed, followed by extraction. However, three weeks following this treatment, the patient presented with a localized extra-oral cellulitis, despite having good intra-oral healing of the extraction socket, with no intra-oral erythema or swelling. The cutaneous lesion was fluctuant, well demarcated and located on the lower right quadrant. It was warm and tender to palpation. The patient was apyrexic, with no systemic involvement (Figure 11).

Following consultation with oral surgery colleagues, it was decided to incise and drain the swelling extra-orally (Figures 12 a and b). Metronidazole and amoxicillin with clavulanic acid were prescribed due to initial failures to resolve the swelling with amoxicillin only. Microbiology and antibiotic sensitivity were requested.

Microbiology results showed heavy growth of mixed anaerobes for which metronidazole was indicated. The sample was negative for actinomyces. At two weeks review the swelling had reduced and the lesion was healing. Subsequent reviews showed healing with minimal scarring (Figure 13). Long-term management will include a referral to plastic surgery with the view of reducing remaining scarring.

Discussion

Although facial cutaneous sinus tracts are commonly of odontogenic aetiology, authors have estimated that 50% of patients are misdiagnosed and subjected to dermatological interventions or long-term antibiotherapy.^5,6 Adequate investigations, including antibiotic sensitivity, are advised in order to determine aetiology accurately and aid in management. Frequently, interventions only lead to temporary resolution, with inevitable recurrence.³ Often, children are initially seen by medical professionals, who may not always recognize the dental aetiology.

Conclusion

This series of cases emphasizes the importance of considering a dental cause in the differential diagnosis of localized chronic inflammatory and purulent skin lesions of the lower face, especially in the submandibular/sublingual triangles and around the lateral border of the mandible. Failure to recognize this nowadays relatively rare presentation of otherwise common dento-alveolar pathology can present a diagnostic quandary which may result in ineffective, unnecessary and prolonged treatment. The resultant delay in resolution can have a significant impact on both physical and psychological well-being.

Why this paper is important to paediatric dentists and general dentists