Monkeypox presenting as a chancre-like rash: A case report

Abstract

BACKGROUND

Since May 2022, outbreaks of monkeypox have occurred in many countries around the world, and several cases have been reported in China.

CASE SUMMARY

A 38-year-old man presented with a small, painless, shallow ulcer on the coronary groove for 8 d. One day after the rash appeared, the patient developed inguinal lymphadenopathy with fever. The patient had a history of male-male sexual activity and denied a recent history of travel abroad. Monkeypox virus was detected by quantitative polymerase chain reaction from the rash site and throat swab. Based on the epidemiological history, clinical manifestations and nucleic acid test results, the patient was diagnosed with monkeypox.

CONCLUSION

Monkeypox is an emerging infectious disease in China. Monkeypox presenting as a chancre-like rash is easily misdiagnosed. Diagnosis can be made based on exposure history, clinical manifestations and nucleic acid test results.

Key Words: Monkeypox, Chancre-Like rash, China, Case report

Core Tip: We reported an indigenous case of monkeypox transmitted by male-male sexual activity, suggesting the beginning of community transmission of monkeypox in the mainland of China. Monkeypox presenting as genital ulcers is easily misdiagnosed as chancre or other skin diseases. Clinicians should improve the awareness of monkeypox to avoid possible misdiagnosis and prevent the spread of monkeypox in the community.

INTRODUCTION

Monkeypox is a zoonotic disease caused by the monkeypox virus (MPXV) that infects both humans and animals. It used to be predominantly prevalent in West and Central Africa. However, since May 2022, there have been multiple global outbreaks of monkeypox with different transmission routes and clinical presentations compared to the classical form[1]. In September 2022, China reported its first imported case, followed by sporadic cases within the country[2]. This article reports a recently diagnosed case of indigenous monkeypox and reviews the relevant literature.

CASE PRESENTATION

Chief complaints

A 38-year-old male pet shop worker presented to our dermatologic clinic with coronary ulcers for 8 d.

History of present illness

Eight days ago, the patient developed a small, painless shallow ulcer near the coronary sulcus of the glans without obvious inducement. The ulcer was not relieved by self-topical mupirocin treatment and became deeper. Seven days ago, the patient developed inguinal lymphadenopathy and fever, with a maximum body temperature of 38.6 °C. He self-administered ibuprofen for symptomatic relief. One day ago, new rashes appeared on the neck and limbs, prompting him to seek medical help at our department.

History of past illness

The patient was healthy in the past.

Personal and family history

The patient had a history of unprotected male-male sexual activity approximately 11 d before the rash onset and denied a recent history of travel abroad.

Physical examination

Physical examination revealed redness and swelling of the pharynx and enlargement of bilateral inguinal lymph nodes. Multiple grayish-white plaques with a central ulceration were observed in the coronal groove of the glans penis, without obvious secretions on the surface (Figure 1A). There were scattered tender papules, papulopustules and crusts on the neck, palms, and inner thighs (Figures 1B and C).

Figure 1 Skin and mucosal lesions on physical examination. A: Multiple grayish-white plaques with central ulcerations on the coronal groove, without obvious secretions on the surface; B and C: Scattered papulopustules with tenderness on the neck and palms.

Laboratory examinations

The treponema pallidum particle agglutination assay, toluidine red unheated serum test, and human immunodeficiency virus antigen antibody combination test (HIV-P24) were negative. The white blood cell count was 6.98 × 10⁹/L, with an atypical lymphocyte proportion of 4%, and the C-reactive protein level was 16.04 mg/L. There were no obvious abnormalities in liver or kidney function. Monkeypox virus quantitative polymerase chain reaction testing was performed on swabs taken from the rash site and throat secretion. The computed tomography (CT) values for the rash on the glans penis and the throat swab were 23 and 37, respectively. The virus was identified as the West African strain by sequencing by the Hangzhou Center of Disease Control and Prevention.

FINAL DIAGNOSIS

Based on the epidemiological history, clinical manifestations, and nucleic acid test results, the patient was diagnosed with monkeypox.

TREATMENT

The patient was admitted to the ward and placed in droplet and contact isolation. Antiviral treatment with acyclovir and symptomatic treatment with celecoxib were administered. Topical application of recombinant human interferon alpha-2b spray was used for antiviral therapy. Four days later, the patient’s body temperature returned to normal, and no new rashes appeared. He was discharged but still needed to continue medication at home and self-isolate.

OUTCOME AND FOLLOW-UP

By telephone follow-up, all the rashes crusted and fell off 14 d after discharge, leaving superficial depressed scars on the neck and hypopigmentations on the other sites. At present, the patient has been released from self-isolation.

DISCUSSION

Monkeypox virus is a double-stranded DNA virus belonging to the genus Orthopoxvirus of the Poxviridae family. Its primary hosts are African rodents. The first case of human monkeypox infection was reported in the Democratic Republic of the Congo in 1970[3]. Subsequently, sporadic outbreaks occurred in some countries in West and Central Africa, with a few travel-associated cases reported in Europe, North America, and Asia[1]. From May 2022, monkeypox started to spread extensively and had outbreaks in multiple nontraditional endemic countries and regions. As a result, in July 2022, the World Health Organization declared the outbreak of monkeypox a Public Health Emergency of International Concern.

Monkeypox can be transmitted through two main routes: animal-to-human and human-to-human transmission. Transmission between humans occurs through the inhalation of large respiratory droplets, close or direct contact with skin lesions, vertical transmission, or indirect contact through fomites[1]. Currently, there is no clear evidence of sexual transmission through semen or vaginal secretions[4]. In the current global outbreak of human MPXV infection, most diagnosed cases are among men who have sex with men, and direct contact with infectious lesions is the main route of transmission[4-6]. Subclinical or asymptomatic monkeypox infections are rare[1]. However, in the 2022 outbreak, approximately half of the transmissions occurred during the presymptomatic stage, indicating a need for further research to determine the possibility of transmission by asymptomatic individuals[1,7]. In this case, the patient engaged in unprotected sexual behavior with a male before the rash appeared, which aligns with male-to-male transmission.

In the 2022 outbreak, the average incubation period after exposure was 7-10 d[4,8-10]. Systemic symptoms are common and typically present as fever, fatigue, or myalgia[1]. These symptoms can occur before or shortly after the onset of rash, although reports of skin lesions without systemic illness have also been observed[5,8]. The rash of monkeypox usually lasts for 2-3 wk. It initially appears as small spots and then evolves into papules, vesicles, and pustules, which crust, dry, and eventually slough off after 7 d to 14 d[1]. Skin lesions can appear on any part of the body, and different stages of lesions may coexist[6]. In previous outbreaks, the rash typically first appeared on the face and gradually spread to the trunk and limbs. However, in the 2022 outbreak, the lesions were mainly located in the anogenital and perioral regions[4,6]. Genital rash in male patients may manifest as one or multiple lesions[5]. Approximately a quarter of patients are concurrently diagnosed with sexually transmitted diseases[4,5]. In this case, the patient’s rash initially occurred in the coronal sulcus, presenting as a chancroid-like genital ulcer, which can often be misdiagnosed as chancroid.

In September 2022, the first imported case of the mainland of China was reported in Chongqing municipality[2]. According to the statistics on the WHO website, as of June 27, 2023, there have been 6 confirmed cases in the mainland of China (https://worldhealthorg.shinyapps.io/mpx_global/). Two recently reported cases of local transmission in the mainland of China were both males who had sex with men[11,12]. In one case, the initial manifestation was gray-white plaques in the coronal sulcus, followed by fever, sore throat, and generalized rash[11]. In the other case, the patient developed erythema, papules, pustules, and ulcers on the penis and pubis three days after the onset of fever[12]. The epidemiological characteristics and clinical presentations of our case were similar to those of the above two cases, with an incubation period of approximately 11 d. The initial presentation is painless ulceration in the coronal sulcus, followed by fever and enlarged lymph nodes one day later. It can be misdiagnosed as syphilis chancre, lymphogranuloma venereum, chancroid, genital herpes, or balanitis. Chancre has an average incubation period of 2 wk to 4 wk and is often solitary with a clean, smooth base and cartilaginous hardness without systemic symptoms. Monkeypox, however, often has multiple rashes, presenting as papulopustules, umbilical-like papules, etc., with surrounding redness and swelling, and often has systemic symptoms before or after the onset of rash[5]. Lymphogranuloma venereum is characterized by small superficial vesicles or ulcers, followed by inguinal lymphadenopathy, ulceration, and suppuration, while lymphadenopathy of monkeypox often resolves within a short period. Chancroid presents as painful, purulent ulcers in the genital area, often accompanied by suppurative lymphadenitis in the inguinal region, whereas monkeypox skin lesions are not associated with severe pain. Genital herpes manifests as multiple vesicles that progress to erosions, which are smaller and shallower than monkeypox lesions. After the onset of generalized rash, monkeypox needs to be differentiated from varicella. Compared to monkeypox, varicella lesions were polymorphic and centripetal distributed, with denser lesions on the trunk than on the face and limbs, and developed rapidly without lymph node enlargement. In contrast, monkeypox skin lesions usually start on the genital area or face and spread in a centrifugal manner, involving the chest, arms and legs, followed by the palms and soles[13]. In this case, there were vesicular eruptions on both palms. Additionally, monkeypox needs to be distinguished from other poxvirus infections, secondary syphilis, pyoderma, and aphthous ulcers[1].

Timely diagnosis is crucial for controlling the spread of monkeypox. The diagnosis of monkeypox is based on a comprehensive assessment of clinical manifestations, epidemiological history, and laboratory testing results. Skin lesion specimens are preferred for testing due to high viral load and positive nucleic acid detection rates[14]. In this case, the nucleic acid test result from the skin lesion had a lower CT value than the throat swab, supporting transmission through close contact. A relatively high proportion of patients with monkeypox were HIV positive or had sexually transmitted diseases[4,5], so testing for HIV and other sexually transmitted infections should be conducted for monkeypox patients. Once diagnosed, the patients should be promptly isolated until all skin lesions crust over and fall off. Monkeypox is self-limiting and generally has a good prognosis. Most patients do not need special treatment, and symptomatic care, such as antipyretic and analgesic therapy, is sufficient. However, monkeypox in individuals with advanced and uncontrolled HIV infection may have a higher risk of developing serious and prolonged illness, which should be given high attention[15]. Effective antimicrobial therapy should be administered for secondary bacterial skin infections. Currently, there are no specific antiviral drugs for treating monkeypox. Antiviral treatment with tecovirimat is preferred for severe cases and immunocompromised individuals[16]. In this case, the patient did not have any other sexually transmitted diseases, and his condition improved after symptomatic antipyretic treatment without complications.

CONCLUSION

In China, monkeypox is a newly emerging infectious disease. Currently, the number of monkeypox cases in the mainland of China is gradually increasing. Clinical physicians need to enhance their understanding of this disease. For individuals with a high-risk exposure history, especially a history of male-to-male sexual contact, and the presence of papules, vesicles, pustules or ulcers around the genital and anal areas, with or without fever and lymphadenopathy, the possibility of monkeypox should be considered. Immediate MPXV nucleic acid testing should be performed to confirm the diagnosis, and the patient should be isolated and treated in time. In addition, it is necessary to improve the reporting and monitoring system, strengthen health education for high-risk populations, and administer vaccines to high-risk individuals when necessary to curb community transmission of monkeypox.