Chancroid: Pathogenesis and clinical findings
Authors: Mina Youakim Reviewers: Elise Hansen Sunawer Aujla Shahab Marzoughi Jori Hardin* * MD at time of publication
Condomless sex
Multiple sexual partners
Genital injury (i.e. cuts, friction)
Micro-abrasions occur in the epidermal tissue of the genital area
Sexual Transmission of Haemophilus ducreyi (H. ducreyi) bacteria from an infected sexual partner
H. ducreyi enters the epidermis through micro abrasions H. ducreyi infects epithelial cells
H. ducreyi secretes Large Supernatant Proteins LspA1 and LspA2 (which inhibit phagocytosis by neutrophils and macrophages)
T cells activate and release cytokines IL-6 and IL-8 Neutrophils are recruited to the site of infection
Local macrophages form a collar around the base of the papule to try to reach and engulf H. ducreyi
↑ Localized buildup of immune cells
While infection persists, H. ducreyi release lipooligosaccharides (LOS)
LOS travels to lymph nodes in the inguinal region Lymph nodes synthesize and proliferate T
cells specific to H. ducreyi antigen Inguinal lymph nodes swell due
to ↑ number of T cells
Inguinal buboes (swollen inguinal lymph nodes)
Neutrophils surround the bacteria and attempt to engulf it
Localized epidermal buildup of neutrophils and H. ducreyi
Papules (small protrusions on the skin)
Continued build-up of H. ducreyi, neutrophils, dead white blood cells (pus), and macrophages
Pustules (pus-filled skin lesion)
↑ Local pressure from growing pustule compresses surrounding vessels
↓ Local blood flow erodes and sloughs off the local epidermal roof
Ulcers (open skin sore)
Sign/Symptom/Lab Finding
Published Feb 8, 2024 on