Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Cervicofacial actinomycosis is an uncommon, chronic, suppurative, and granulomatous bacterial infection. It is often of dental origin and tends to mimic other dental infections, granulomatous disorders, and cancers. The initial diagnostic workup, predicated upon imaging and tissue biopsies, is frequently nonspecific. A definitive diagnosis is usually rendered only after surgical excision and histologic examination of the cervicofacial mass. We propose a classification of three stages: localized infection without sinus involvement, localized infection with sinus involvement, and disseminated infection, to facilitate recognition, diagnosis, and early aggressive treatment. Untreated infection may be lifethreatening. Therapy may require long-term antibiotics; however, many cases may also necessitate complete surgical excision.

Since the emergence of mRNA COVID-19 vaccines, various secondary cutaneous reactions have been reported. 1,2 Commonly observed cutaneous reactions include local injection-site erythema or discomfort, as well as urticarial and morbilliform eruptions. [1][2][3] Less frequent sequalae include perniosis, herpes simplex virus reactivation, flares of psoriasis, and pityriasis rosea-like reactions. 1,4 We report a 66-year-old female with hypertension, hypothyroidism, and hypercholesterolemia, who developed firm, tender, 4-5 cm deep-seated nodules on the right superior medial popliteal fossa and bilateral anterior tibia, 10 days after receiving the first dose of the COVID-19 Moderna mRNA-1273 vaccine (Figure 1). The patient provided informed consent to publish this case. By the time of medical evaluation, some nodules had begun to fade, and the patient was otherwise well, without symptoms of COVID-19 infection. The clinical impression was erythema nodosum (EN), and incisional biopsy of the nodule at the right superior medial popliteal fossa was performed 3 days later. One day prior to biopsy, COVID-19 PCR nasopharyngeal testing was negative. Histologic sections demonstrated widened subcutaneous septae containing an inflammatory infiltrate of lymphocytes, neutrophils, eosinophils, and histiocytes, compatible with EN. Routine hematologic and chemistry studies were unremarkable.Erythrocyte sedimentation rate, C-reactive protein, and circulating rheumatoid factor were normal. Anti-nuclear antibodies, anti-doublestranded DNA antibodies, anti-streptolysin antibodies, and hepatitis B

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One should consider secondary syphilis in the differential diagnosis of an eruption resembling EM.