Abstract
Pityriasis rosea (PR) is an acute self-limited exanthem characterized by oval erythematous patches with scale and may be difficult to differentiate from secondary syphilis. A rapid plasma reagin (RPR) test can be used to rule in secondary syphilis with high sensitivity and specificity. A retrospective study was performed on patients at Weill Cornell Medicine, who were diagnosed with PR from 2000 to 2016 and also received RPR testing at the time of diagnosis. The objective was to assess the frequency of secondary syphilis when the initial clinical impression was PR. Only 2/142 patients (1.4%) had a reactive RPR test. Based on our results, we advocate that careful social and sexual histories be taken in all patients presenting with atypical PR and syphilis screening performed if risk factors are present.
Pityriasis rosea (PR) is an acute self-limited exanthem characterized by oval erythematous patches with scale, typically beginning with a ‘herald patch’. There is evidence to suggest that PR is associated with reactivation of human herpesvirus (HHV) 6 and 7. 1 However, it should be noted that detection of HHV-6 or -7 serology in a skin sample signifies that the person has been exposed to the virus but may not be indicative of active infection or causation.2,3 Since histopathologic features are not specific, the diagnosis of PR is based on characteristic features from the history and physical examination. Clinically, PR may be difficult to differentiate from secondary syphilis,4,5 but a rapid plasma reagin (RPR) test can be used to rule in the latter with 100% sensitivity and 85–99% specificity. 5
Methods
A retrospective study was performed on patients at Weill Cornell Medicine, who were diagnosed with PR from 2000 to 2016 and also received RPR testing at the time of diagnosis. The institutional review board approved the protocol. The objective was to assess the frequency of secondary syphilis when the initial clinical impression was PR. The Weill Cornell Medicine Information Technologies and Services cohort discovery program (i2b2) was used to search all Weill Cornell outpatient electronic medical records for those patients with a diagnosis of PR and subsequent RPR testing. One hundred and forty-two charts met inclusion criteria and were reviewed for demographics, social and sexual history, and result of RPR testing.
Results
Summary of patient demographics, social history, sexual history, and RPR testing in patients diagnosed with PR.
IV: intravenous.
Unless otherwise noted, data are reported as number (percentage) of respondents.
Patients with history of one or more of the following: gonorrhea, chlamydia, herpes simplex, syphilis, HIV, molluscum contagiosum, genital warts, or hepatitis B.
Safe sex practices entail barrier methods to decrease likelihood of sexually transmitted infection transmission which entail one or more of the following: male or female condoms, dental dams for oral sex, or gloves for manual penetration.
Only 2/142 patients (1.4%) had a reactive RPR test. One patient was a 27-year-old Latino who was human immunodeficiency virus (HIV)-positive, smoked and drank alcohol, but had an unknown sexual history, including sexual practices and STI history, and sexual orientation. He denied using IV drugs. At the first visit, he presented with several erythematous macules and papules, some with collarettes of scale, on his chest, abdomen, back, upper extremities, and upper thighs. A clinical diagnosis of PR was made, a RPR was drawn, and the patient was advised to use emollients and follow up in 4–6 weeks. Since the RPR was reactive and the titer was 1:32, the patient was asked to return for confirmation and treatment. At a follow-up visit five days later, he presented with confluent erythematous papules on the chest, back, and abdomen, with a few erythematous papules on the face and neck. He also had left inguinal lymphadenopathy. An FTA-ABS was drawn and he was treated with doxycycline hyclate 100 mg twice daily for 14 days. The FTA-ABS was positive, but the patient was lost to follow up. The other patient was a 36-year-old homosexual Caucasian man, with an unknown number of sexual partners but practiced safe sex, had an unknown history of STI, drank alcohol, but did not smoke or use IV drugs. He presented initially with faint macules on the abdomen and an erythematous plaque with scale on the glans penis. A shave biopsy of the penile rash showed a lichenoid and pustular dermatitis. The patient was prescribed triamcinolone ointment to the penis and counseled to use emollients on the abdomen. On follow up, 11 days later, the penile rash had not improved and the patient presented with increasing numbers of erythematous oval macules on the abdomen. The differential diagnosis included secondary syphilis, PR, and a drug reaction and RPR was drawn. The RPR was positive with a titer of 1:32 and the patient returned for treatment and confirmatory testing. An FTA-ABS was drawn and he was treated with Benzathine Penicillin G 2.4 million units. His FTA-ABS was positive and he was seen in follow up one week following treatment at which point his rash had resolved.
Discussion
A previous prospective study was conducted to evaluate the frequency of secondary syphilis in patients with a clinical diagnosis of PR. While 3/50 patients (6%) had positive RPR tests, none of the rashes were attributed to syphilis. All three patients had a documented history of treated syphilis before diagnosis of PR. 6
In the present study, 2/142 patients (1.4%) had positive RPR tests, positive follow-up treponemal-specific testing and an initial clinical diagnosis of PR. While serology supports a diagnosis of secondary syphilis in these patients, no skin biopsy was performed on the rash in either patient to confirm the diagnosis, so it cannot be determined with certainty whether the rashes were due to syphilis or syphilis with concurrent PR. For the 27-year-old Latino man, the HIV-positivity, papular rash (collarettes were no longer present at the follow-up exam), and lymphadenopathy make a diagnosis of secondary syphilis more likely than PR. For the 36-year-old Caucasian man, his homosexuality, erythematous oval macules without scale, penile rash, and rapid response to penicillin, also make a diagnosis of secondary syphilis more probable.
Primary and secondary syphilis cases have been increasing since 2000, with 19,999 cases reported in 2014. In 15% of people infected with syphilis, progression to the late stage disease may occur resulting in cardiovascular and central nervous system dysfunction. Our study demonstrated that only 1.4% of patients with an initial clinical diagnosis of PR likely had secondary syphilis instead. These patients also had clinical features that were atypical for PR (lymphadenopathy in one patient, lack of scale in both patients). Since the likelihood of an active syphilis infection when a patient presents with typical PR without mucosal, palmoplantar, or lymph node involvement is minimal to none,
6
we advocate that careful social and sexual histories be taken in all patients presenting with atypical PR (no scale, lymphadenopathy, mucosal lesions, palmoplantar rash) and syphilis screening performed if risk factors are present. Our recommendation stems from the US Preventive Services Task Force recommendation for screening of asymptomatic, nonpregnant individuals with increased risk factors for syphilis,
5
as well as similar guidelines from the Centers for Disease Control and Prevention (CDC).
7
A proposed algorithm for syphilis screening when a patient presents with a clinical diagnosis of PR is shown in Figure 1.
Proposed algorithm for syphilis screening in patients diagnosed with Pityriasis rosea (PR) clinical presentation.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.