Syphilic balanitis of Follman presenting as a painful erosive balanitis with negative treponemal serology

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A 38-year-old man presented with a painful genital ulcer of 16 days duration. He had a history of psoriasis and asthma, with no new medication introduced recently. There was no history of drug abuse or human immunodeficiency virus infection. He reported onset of symptoms seven days after unprotected oral and anal insertive sex with another man. Clinical examination showed a large erosive, well-defined balanitis extending onto the foreskin [Figure 1] associated with firm and mobile right inguinal lymphadenopathy. Syphilis serology performed five days after the onset of the genital ulceration showed a negative Treponema pallidum Haemagglutination Assay (TPHA) and a negative Venereal Disease Research Laboratory (VDRL). Bacteriological and mycological samples were negative too. A biopsy of the glans penis was therefore performed. Histological examination showed epithelial ulceration associated with infiltration of the dermis consisting of neutrophils, lymphocytes, as well as a few histiocytes and plasma cells [Figure 2]. There was also small-vessel vasculitis. Anti-herpes immunostaining was negative, but the anti-treponemal antibody revealed the presence of numerous treponemes in the dermis, perivascular spaces, and vascular endothelium [Figure 3]. The diagnosis of primary syphilis was thus made, in a form of syphilitic balanitis of Follman. A second syphilis serology made 1 month after the onset of the genital ulceration and before the treatment revealed a positive TPHA at a titre of 160 and a negative VDRL. The patient was treated with a single dose of intramuscular 2.4 million units of benzathine penicillin G, resulting in complete regression of the balanitis. A syphilis serology performed three months later during follow-up showed a positive TPHA at a titre of 80 with a negative VDRL.

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Figure 1:

Erosive balanitis with extension to the foreskin.

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Figure 2:

Epithelial ulceration associated with infiltration of the dermis consisting of neutrophils, lymphocytes, a few histiocytes and plasma cells, associated with a small-vessel vasculitis (Haematoxylin and eosin, 100x).

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Figure 3:

Treponemes (Immunohistochemistry, 100x) spirochete detected in the chorion of the ulceration.

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Syphilis is a sexually transmitted infection caused by Treponema pallidum (TP), the incidence of which has risen sharply worldwide in recent years.¹ The first stage of the disease (or primary syphilis) is classically characterised by an indurated, clean, painless ulceration, in the weeks following unprotected sexual intercourse.² We report here a syphilitic balanitis of Follmann, which corresponds to one of the possible infrequent manifestations of primary syphilis. From our point of view, this observation is interesting for two reasons. Firstly, it is important for clinicians to be aware of the different clinical manifestations of syphilis, given the current epidemic worldwide. For example, syphilitic balanitis of Follman can be difficult to diagnose because, unlike the “classic” syphilitic chancre, it is extensive, superficial, and painful.³ Differential diagnoses include herpetic primary infection, fixed drug eruption, and caustic balanitis.² It is therefore essential to systematically question any patient with genital ulceration about recent unprotected sexual intercourse and potential sexual risk factors. Secondly, syphilis serology was negative at the time of the first consultation. In a recent study of the serological status of patients with primary syphilis, 60% of patients had a negative nontreponemal test and 36% had both negative treponemal and nontreponemal tests.⁴ It is therefore essential to use direct diagnostic assays in order to detect the presence of TP when primary syphilis is suspected with non-contributory serology. Nowadays, the most effective direct diagnostic assay for the detection of Treponema pallidum is polymerase chain reaction, although it is not yet used in routine clinical practice.⁵ Darkfield microscopy can also be used in some specialised centres even if its specificity is lower for oral and anal locations due to saprophytic spirochetes.⁶ In conclusion, syphilitic balanitis of Follman is a clinical entity of primary syphilis that dermatologists should be aware of in the current epidemiological context of syphilis.