A biopsy of the skin was consistent with folliculitis, but a dental panoramic x-ray revealed an abscess of tooth number 30, which is on the right side. This combination of findings was consistent with a dental sinus.
This unusual diagnosis is most common in adults and arises from dental disease in the mid mandibular pre-molars. It will appear as an abscess or crusted papule and can occur in the lower jaw, neck, or occasionally, the mid cheek. Children are rarely affected. Because the sinus opening relieves pressure from the dental abscess, there is often little to no pain.
It can be challenging to convince a patient that his or her skin lesion derives from dental disease. Often, though, patients are glad it is not cancer. Patients should be referred to an endodontist for a work-up and a root canal, which is the preferred treatment. If a root canal is not feasible, dental extraction will lead to cure.
In this case, the patient promptly underwent a root canal and was cured in 2 weeks. The scar from the papule can have a depressed appearance (FIGURE 2), which can be addressed with excisional scar revision once the underlying abscess is cured.
Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained). Dr. Karnes is the medical director of MDFMR Dermatology Services, Augusta, ME.