Primary Cutaneous Diphtheria as a Rare Cause of Infectious Ulceration

A 51-year-old female patient presented due to a several-week history of ulcerations with a punched-out appearance on the extremities (figure). The patient had returned from vacation in Sri Lanka 3 weeks previously. On the basis of suspected pyoderma, bacteriological swabs were taken and calculated oral antibiotic therapy with clindamycin 3 × 600 mg initiated. The bacteriological swab revealed a mixed infection of Corynebacterium diphtheriae gravis (high bacterial count), MRSA, and Streptococcus pyogenes. Diphtheria toxin gene real-time polymerase chain reaction was negative, which can be the case in cutaneous diphtheria and may be due to loss of the toxin-carrying phage. Although positive vaccination status, which this patient had, creates antitoxic immunity, it does not provide protection against local infection or colonization. All three bacteria were sensitive to clindamycin, resulting in rapid resolution. Cases of reportable cutaneous diphtheria are often seen in individuals returning from (sub)tropical regions. The first outbreak of diphtheria in Germany for 40 years was documented in 2019 following skin-to-skin transmission between siblings with a Somali migration background.

Figure.

Clinical examination revealed multiple ulcerations with a punched-out appearance and the dried residues of grayish-white membranous plaques at the margins.

Translated from the original German by Christine Rye.

Cite this as: Placke JM, Chapot V, Sondermann W: Primary cutaneous diphtheria as a rare cause of infectious ulceration.