A 30-year-old man was referred to our dermatology clinic for assessment of a suspected drug hypersensitivity rash. He had sustained 2 minor traumatic brain injuries over the past 2 years and had been taking several medications for headache including acetaminophen, nonsteroidal anti-inflammatory drugs, and gabapentin. He was also followed by a neurologist and received botulinum toxin injections for his pain. He was taking bilastine for the rash but found no observable benefit. Otherwise, he was healthy, with anaphylactic allergies to wasps and hornets and a possible allergy to penicillin (he had been given penicillin after a wasp sting and had noted a potential rash).
He gave a 2- to 3-month history of erythematous macules beginning over his abdomen, spreading quickly to his entire torso and extremities, including his palms. There was no pruritus, pain, or blistering. He denied intraoral or genital involvement. He was otherwise systemically well except for his postconcussion symptoms. He believed that the macules got darker when exposed to water.
Findings of a physical examination demonstrated a striking full-body, erythematous, nonscaling rash with a substantial annular pattern (Figures 1 and 2). His face was spared. He demonstrated mild dermographism but no Darier sign. He declined a genital examination, but there was no intraoral pathology and his nail findings were unremarkable.
Full-body erythematous, nonscaling rash with substantial annular pattern on torso
Full-body erythematous, nonscaling rash with substantial annular pattern on arms and hands
Upon being asked pointed social history questions, our patient disclosed he had had multiple sexual partners and while he was not taking preexposure prophylaxis, he and his family physician were diligent in doing HIV tests every 3 months and he had had a negative result 2 months prior. He had also had negative nucleic acid amplification test results for Neisseria gonorrhoeae and Chlamydia trachomatis. His Venereal Disease Research Laboratory (VDRL) test result from 6 months ago was nonreactive.
Our differential diagnosis at the time included mastocytosis, drug hypersensitivity reaction, and generalized granuloma annulare.
We ordered a new VDRL test and hepatitis serology testing and performed a 4-mm punch biopsy. Before the biopsy findings were reported, the VDRL test result came back as reactive, with a positive rapid plasma reagin titre of 1:32. A diagnosis of secondary syphilis was made. Due to his documented allergy to penicillin, he was prescribed 14 days of oral doxycycline and the rash abated. Histopathology findings demonstrated a subtle vacuolar interface pattern with lymphoplasmacytic infiltration, but immunoperoxidase staining did not reveal treponemes.
Discussion
Secondary syphilis usually manifests 2 weeks to 6 months after exposure. It most commonly presents as a diffuse, symmetric maculopapular rash that may be concurrent with the chancre of primary syphilis. Generalized lymphadenopathy, patchy alopecia, and mucous membrane lesions such as condylomata lata may appear. While neuropsychiatric symptoms are most notable in the tertiary stage, one can see cranial nerve palsies (optic and facial), ophthalmic sequelae, meningitis, and changes to mental status or memory in the secondary stage.1 Our patient’s concussive symptoms started well before his negative VDRL test result 6 months before his appointment.
Confirmed syphilis cases are increasing in Canada: there were 11,268 reported cases in 2021 (30 per 100,000) compared with 4132 in 2017.2 Although cases predominantly involve gay men, bisexual men, and men who have sex with men, we are also seeing a rise in cases in heterosexual populations.3 This has coincided with an increase in the number of pregnant women with positive test results on antenatal screening (96 cases of early congenital syphilis were reported in 2021, compared with 7 in 2017).2 It is imperative to screen and treat these patients appropriately, as congenital syphilis has lifelong sequelae and neurosyphilis can be life threatening years after infection.
Syphilis is curable with antibiotics (intramuscular penicillin, oral doxycycline, or ceftriaxone), although the length of treatment depends on the stage. Patients should also be counselled on the Jarisch-Herxheimer reaction, which occurs upon lysis of the treponeme and can manifest as fever and systemic symptoms (chills, rigours, myalgias, arthralgias) with worsening rash or chancre.4 There is no test of cure, but guidelines recommend re-testing 6 and 12 months after treatment to ensure titres have fallen.1
Conclusion
This report described a case of syphilis in a patient presenting with an unusually extensive rash. The incidence of syphilis is increasing in Canada, and it is important to recognize it early to prevent long-term sequelae.
Footnotes
Competing interests
None declared
- Copyright © 2023 the College of Family Physicians of Canada
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