Chancre mou

Chancroid is a bacterial sexually transmitted infection characterized by painful genital ulcers, resulting from infection with the fastidious Gram-negative streptobacillus Haemophilus ducreyi ^[1]. It is a highly infectious genital ulcerative condition that spreads through direct contact ^[1][2].

The illness presents with painful sores confined to the genital region, with about half of infected men showing a single ulcer and women often having four or more with fewer symptoms ^[1]. Roughly one-third of those infected develop enlarged inguinal lymph nodes, and half of these progress to ruptured nodes forming draining abscesses known as buboes ^[1]. Lesions are local without systemic manifestations, and the initial ulcer may be confused with the hard chancre of syphilis ^[1].

Chancroid is primarily found in developing countries and is most common in low socioeconomic groups associated with sex work ^[1]. Its prevalence has fallen in the United States and globally, yet intermittent outbreaks persist in the Caribbean and Africa ^[1][2]. In Western nations, occurrence is very low, with estimates around one case per two million population, and in the US it has been isolated in up to 10% of genital ulcers from STI clinics in some cities ^[1]. Surveillance in endemic areas with diagnostic capacity shows a marked decline, but most regions lack laboratory diagnostics to support etiological tracking ^[2].

The infection passes between individuals solely through sexual contact, though accidental hand transmission has been reported ^[1]. It is a sexually transmitted disease found in populations with high sexual activity such as sex workers ^[1][3]. Having chancroid also increases the risk of transmitting and acquiring HIV ^[2].

Strategies applied in high-activity populations include condom use, azithromycin prophylaxis, syndromic management of genital ulcers, and treatment of patients with reactive syphilis serology, as demonstrated in Thailand ^[1]. Sexual partners should be treated whether or not they show symptoms if unprotected intercourse occurred within 10 days before symptom onset ^[1]. Because the pathogen spreads through sexual contact, reducing exposure via barrier methods and partner treatment is central to control ^[1].

1. 1 Wikipedia contributors. Chancroid - Wikipedia [Internet]. Wikipedia. cited 23 Oct 2026. Available from: https://en.wikipedia.org/wiki/Chancroid
2. 2 Lewis DA et al. Chancroid. Clin Dermatol. 2026 Jan-Feb. PMID: 41046959. doi: 10.1016/j.clindermatol.2025.09.017. PubMed: https://pubmed.ncbi.nlm.nih.gov/41046959/
3. 3 Ogale YP et al. A Sore Subject? An Examination of National Case-Based Chancroid Surveillance. Sex Transm Dis. 2023 Aug 1. PMID: 37010821. doi: 10.1097/OLQ.0000000000001814. PubMed: https://pubmed.ncbi.nlm.nih.gov/37010821/