Secondary syphilis presenting as Syphilide psoriasiforme: lessons from the older syphilology literature.

It is essential for health care providers to be familiared with the full spectrum of clinical presentations of syphilis. We present herein a case of syphilide psoriasiforme, an uncommon but well recognized clinical presentation of secondary syphilis. A 46-year-old HIV-infected female patient was referred to our attention with a presumptive diagnosis of palmoplantar psoriasis. On examination, there were exuberant pinkish-red papules and plaques covered with a thick silvery scale in the palms, flexor surfaces of the wrists, and the medial longitudinal arches of the feet. Serological and histopathological analyses uncovered the diagnosis of syphilis. Clinical remission was obtained after treatment. A detailed review of the literature on syphilide psoriasiforme, including descriptions from older syphilology textsis provided. The present case report emphasizes the need for clinicians to have a heightened awareness of the varied and unusual clinical phenotypes of syphilis.

Acquired syphilis is a sexually transmitted infection caused by the spirochete Treponema pallidum, subspecies pallidum. It has a triphasic natural history in which a secondary stage of florid mucocutaneous manifestations follows a primary ulcer (chancre), and preceeds a tertiary stage of a slowly progressive, destructive inflammatory process that can affect any organ. Syphilis has been appropriately termed “the great imitator” due to its heterogeneity of presentation and mimicry of other conditions. We present herein a case of syphilide psoriasiforme, an uncommon but well recognized clinical presentation of secondary syphilis.

A 46-year-old HIV-infected female patient presented with a five-month history of non-pruritic, erythematous and lightly scaling plaques over the palms and soles, mainly the medial longitudinal arches of the feet (Figure 1). She had a diagnosis of HIV infection made 6 years before and a long history of poor adherence to antiretroviral treatment. Her current treatment combination was lamivudine, tenofovir and ritonavir-boosted atazanavir. She was also on sulfamethoxazole-trimethoprim as prophylaxis of opportunistic complications and risperidone for a bipolar disorder. Her current CD4 cell count was 141 cells/mm3 and the plasma HIV viral load was 80 copies/mL (1.9 log), which indicated ongoing viral replication, albeit at a value close to the lower limit of detection of the assay (40 copies/mL). A rapid point-of-care syphilis test was reported to be negative, as well as previous serological tests for syphilis. The skin lesions were treated with fluconazole and prednisone at another facility, but the lesions did not remit. Two months later, there were new lesions and the previous ones were larger and tender (Figure 2). She was then referred to our attention with a presumptive diagnosis of palmoplantar psoriasis.

Figure 1

Clinical images of a 46-year-old female patient. Erythematous and slightly scaly plaques are seen over the palms (A), soles and medial longitudinal arches of the feet (B).

Figure 2

Two months later there were exuberant pinkish-red scaly lesions on the palms, with circinate borders in the medial longitudinal arches of the feet.

On clinical examination, there were exuberant pinkish-red papules and plaques covered with a thick silvery scale in the palms and flexor surfaces of the wrists. In the medial longitudinal arches of the feet, there were large plaques with a thick silvery scale and circinate borders (Figure 2). There were no oral lesions or lymphadenopathy. Laboratory evaluation showed no serological evidence of hepatitis B or hepatitis C infections, but the Venereal Disease Research Laboratory (VDRL) titer was reactive at a titer of 1/128. A novel rapid point-of-care syphilis test was also positive. Histopathological analyses of skin biopsy samples revealed lichenoid dermatitis with perivascular inflammatory infiltrate in the reticular dermis, which was rich in plasmocytes (Figure 3). Spirochetal structures were uncovered by a Warthin-Starry staining (Figure 3C). Deepening the data of the patient's past history, the patient could not recall having had a primary chancre. A clinical diagnosis of secondary syphilis presenting as syphilide psoriasiforme was made. Skin lesions rapidly regressed after the administration of 2.4 million units of intramuscular benzathine penicillin G (Figure 4). The VDRL titers dropped two-fold within three months. No Jarisch–Herxheimer reaction occurred.

Figure 3

Histopathological analyses of skin biopsy samples: A) Hematoxylin and eosin staining reveals hyperkeratosis, parakeratosis, cellular debris in the corneal layer, saw tooth acanthosis, vacuolization of the basal cell layer, apoptotic keratinocytes, as well as an inflammatory infiltrate composed of lymphocytes, macrophages and plasma cells in the dermo-epidermal junction. There are also melanophages in the superficial dermis. Original magnification: x 100; B) Hematoxylin and eosin staining shows an inflammatory infiltrate rich in plasmocytes (white arrows) and with abundant endothelial edema (black arrows). Original magnification: x 400; C) Warthin-Starry stain uncovers a spirochete.

Figure 4

Complete remission of the lesions on the palms (A) and soles (B).

Few case reports of secondary syphilis simulating psoriasis are available on modern biomedical databases – . Some of these patients were initially treated as psoriasis until a final diagnosis of syphilis was reached. Solak et al. reported the case of a 43-year-old male patient with syphilide psoriasiforme who was misdiagnosed and treated as palmoplantar psoriasis for 2 years. Similarly, Gianfaldoni et al. described the case of a 45 year-old male patient who was initially diagnosed and treated as a palmoplantar psoriasis before the correct diagnosis of syphilide psoriasiforme was made.

The older syphilology literature is rich in references on syphilide psoriasiforme. Authors from the XIX and early XX centuries observed that palm and sole syphilids are eventually covered by an intense scaling that give the lesions an overall psoriatic aspect . Writing about his experience at the dermatology unit of Saint Louis Hospital in Paris in the XIX century, Eugène Guibout reported the existence of a clinical phenotype of syphilis that he named psoriasis syphilitique or syphilide psoriasiforme, which could be either a manifestation of early or late syphilis . He stressed that his observations on the syphilitic nature of the lesions “leave no doubt on this respect” . Writing earlier in the XIX century, Alfred Hardy had pointed out in his Leçons sur les Maladies de la Peau that “psoriasis syphilitique has a preference for the hands and feet” .

In his Traité de la Syphilis, Alfred Fournier proposed that the condition be named syphilide psoriasiforme, as he considered psoriasis syphilitique “a hateful term” . He explained that syphilide psoriasiforme is a variety of the papular syphilide. Papular syphilitic lesions may present with variable degrees of scaling. Most commonly, a thin grayish or whitish scale covers the papule that may form the so-called collerette de Biett when the lamellae fractures circularly. In some rare situations, however, the covering scale “becomes abundant, if not overabundant”. As he explained, the papule is then “overcome by a thick and adherent white crust” and “definitely assumes the physiognomy of psoriasis, as testified by several (wax) specimens conserved at Saint-Louis Hospital Museum” (Figure 5). He then explained that “it is impossible not to consider these lesions as psoriasis at a first glance” .

Figure 5

Dermatological wax moullage models of syphilide psoriasiforme rash from Musée des Moulages, Hôpital Saint-Louis, Paris: A) Syphilide palmaire psoriasiforme; B) Syphilide plantaire psoriasiforme. Reproduced with permission (©F.Marin, P.Simon, Musée des Moulages, Hôpital Saint-Louis, Paris, AP-HP).

Still in his Traité de la Syphilis, Fournier classified the papular syphilids according to their site of presentation. One of these varieties is the syphilide palmaire et plantaire . Again, he refuted any terminology that might suggest a psoriatic etiology of such disorder. This clinical variety of secondary syphilis has three main characteristics: the presence of lesions exclusively on the hands and feet, the remarkable symmetry of the lesions and the existence of lesions in both hands and both feet (even though some patients have lesions only on the hands or only on the feet). Fournier also observed the distress experienced by the crackling and fissuring of the palmar lesions of the patients whose activities involve manual labor, such as laundresses, diggers and blacksmiths. Plantar lesions have a preference for the medial part of the soles. These plantar lesions persist for some time simply as “reddish, pink-grayish or pink-yellowish stains” that are so faint that in some patients “need to be guessed” (Figure 5), reminding us of our patient's initial presentation (Figure 1B). The dorsal aspects of the hands and feet are not affected. Fournier then asked “why?”. Only to answer himself: “I ignore” .

It should be kept in mind that secondary syphilis may supervene on a patient with a previous diagnosis of psoriasis. Palmoplantar lesions of psoriasis guttata have been found to clinically similar to secondary syphilis . Additionally, secondary syphilis may be a trigger for exacerbation of psoriasis . As pointed out by John H. Stokes in the 1934 edition of his classic treaty Modern Clinical Syphilology, some of the features that aid in distinguishing psoriatic lesions from secondary syphilis include the presence of scalp, elbow and knee lesions, the occurrence of polymorphic lesions, the emergence of minute hemorrhagic points on the curettage of the scale, and the psoriatic nail changes .

The present case report on a syphilide psoriasiforme emphasizes the need for clinicians to have a heightened awareness of the varied and unusual clinical phenotypes of syphilis. The careful reading of classic syphilology authors may shed light on unusual and atypical presentations of syphilis that physicians may encounter nowadays.