A case of secondary syphilis with HIV, resembling borderline lepromatous leprosy.

We are reporting an unusual case of secondary syphilis, in a homosexual male patient, which resembled borderline lepromatous leprosy, and in whom the diagnosis was considered on clinical grounds. The patient also had concomitant HIV infection, with asymptomatic neurosyphilis. His rapid plasma reagin test was reactive in 1:128 dilution. He improved with three standard, weekly injections of benzathine penicillin, along with 2 g of intravenous ceftriaxone daily for 15 days. This case is being reported to highlight the need for a high index of suspicion in diagnosing unusual cases of secondary syphilis, especially in those with concomitant HIV infection.

INTRODUCTION

Secondary syphilis associated with HIV could be a diagnostic conundrum.[1] Moreover, secondary syphilis should be considered in the differential diagnosis of any dermatosis which is atypical.[2] We are reporting a case of secondary syphilis, without any history of a primary lesion, that resembled borderline lepromatous (BL) leprosy, and in whom the diagnosis was considered on clinical grounds.

CASE REPORT

A 57 year old middle class male patient presented with asymptomatic, generalized, annular plaques present for 2½ months, and without constitutional symptoms. He had consulted various doctors, but without relief. A skin biopsy performed outside was reported as tuberculoid leprosy. The plaques were situated on the front and back of trunk [Figure 1], on the upper extremities and thighs, and on the face, with confluent nodules on the forehead. The larger plaques were 4-5 cm in size, and had succulent papulonodules at the margin [Figure 1, site of biopsy 1]. Other plaques had scaly margins, which were rolled out [Figure 1]. On the right forearm there were eroded, annular plaques, with sharply raised overhanging, and scaly margins [Figure 2]. The differential diagnosis included sarcoidosis and mycosis fungoides, besides BL leprosy. However, on noting that the plaques showed increased sensitivity to pain (Buschke-Ollendorf sign), secondary syphilis was also considered. Moreover, a generalized and epitrochlear lymphadenopathy was also noted, but there were no mucous patches or condyloma lata.

Figure 1

Plaques on the back of trunk before treatment. The plaque with a scaly margin is seen on the left scapular area (biopsy 2)

Figure 2

The eroded, annular plaques with scaly margins, on the right forearm, before treatment

Subsequent investigations confirmed the diagnosis of secondary syphilis, as his rapid plasma reagin (RPR) test was reactive in 1:128 dilution, his skin smears were negative for lepra bacilli, and his Treponema pallidum haemagglutination test was also positive. On direct questioning, the patient admitted to promiscuous homosexual behaviour. He also had concomitant HIV infection by the ELISA test, and his CD4 count was 269 cells/cmm. Other abnormal results were SGOT of 90 IU/L and SGPT of 80 IU/L. His tests for hepatitis B and C were negative. His chest X-ray was normal, and his eye, cardiovascular, and neurological examination did not reveal any abnormality. His cerebrospinal fluid (CSF) examination revealed asymptomatic neurosyphilis, with 10 cells/cmm and 50 mg protein/dl, but with a negative CSF Venereal Disease Research Laboratory (VDRL) test.

His skin biopsy performed from two different plaques showed essentially similar features, with the presence of a florid subepidermal granulomatous infiltrate without a free Grenz zone, in biopsy 2. A few Langhans and multinucleate giant cells were also seen, apart from a periappendageal and perineural granulomatous infiltrate rich in plasma cells [Figure 3, biopsy 1] that was breaking up the arrectores pilorum muscle. In addition, endothelial swelling, with luminal narrowing, and a perivascular infiltrate of lymphocytes and plasma cells was also present. The special stain was negative for lepra bacilli. The skin biopsy was consistent with a diagnosis of granulomatous secondary syphilis.

Figure 3

A periappendageal and perineural infiltrate (H and E ×200, biopsy 1)

The patient received three weekly injections of 2.4 million units of intramuscular benzathine penicillin, along with 2 G of daily intravenous ceftriaxone for 15 days. He did not develop any fever after any of his injections (negative Jarisch-Herxheimer reaction). This treatment was followed by anti-retroviral therapy. The plaques on the back had flattened 50% within one week of the penicillin injection [Figure 4] and the eroded plaques on the forearm had regressed 70% by then. Within 20 days, the plaques had almost totally flattened, and 1½ months later, only hyperpigmented macules were remaining. After 4 months his repeat RPR had fallen to 1:64 dilution, and his CD4 count had risen to 547 cells/cmm. When last seen one year later, his RPR had further fallen to 1:16 dilution, and there was no recurrence of his skin lesions. He remained in good health.

Figure 4

Partial regression of plaques one week after treatment

DISCUSSION

This case has illustrated the dictum that syphilis is the great imitator. Its diagnosis is even more difficult when there is associated HIV infection.[13] A high index of suspicion and a thorough clinical examination are essential for diagnosis. Hence, it is suggested that an RPR/VDRL test should be routinely performed in any atypical dermatosis.[2] In our patient, there was both a clinical and a histological resemblance to leprosy, as well as atypical features.[2] However, on careful evaluation, a diagnosis of granulomatous secondary syphilis could have been considered, as there were numerous plasma cells, associated with changes in the blood vessels.[24] There have been similar reports of secondary syphilis resembling BL or LL leprosy, with,[4] . and without associated HIV.[56] Syphilis, when associated with HIV, could be more severe and unusual,[137] with an increased risk of neurological involvement,[38] hastening of the late stage,[48] and treatment failure.[38] Hence, treatment as for late syphilis has been advocated in cases of secondary syphilis, with HIV,[8] along with a mandatory CSF test.[2] We treated his asymptomatic neurosyphilis with the alternative recommended dose of ceftriaxone,[9]. and also decided to complete the course of benzathine penicillin, as it had already been started. Syphilis facilitates the transmission of HIV, by increasing the viral load, and reduces the CD4 count, which increases after the syphilis is successfully treated.[10] In conclusion, it may be stated that this case has demonstrated the primacy of the time-tested method of a thorough clinical examination and history, followed by the relevant and interpretative investigations, and a good, clinico-pathological correlation for making the correct diagnosis in any unusual dermatosis.

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Conflicts of interest

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