Chancroid

Chancroid (third venereal disease) is a classic STD caused by Haemophilus ducreyi, sexually transmitted, characterized by one or more painful genital ulcers with suppurative inguinal lymphadenopathy.

Common Symptoms

Vesicle; papule; station doctor; purulent pseudomembrane; pustule; heat pain; penile/penial edema; vulvar ulcer; purulent discharge

Causes and Pathogenesis

(1) Etiology: H. ducreyi is a Gram-negative short rod 1-1.5 × 0.5-0.6 µm, ends rounded, often in chains/parallel rows ("fish school"), non-motile, non-flagellated, non-spore, non-capsule; facultative anaerobe requiring X factor (hemin) but not V factor—hence "blood-lover". Nitrate reductase-positive, oxidase/alkaline phosphatase-positive, catalase/porphyrin-negative; heat-sensitive (killed at 65°C/boiling). (2) Pathogenesis: incompletely understood; bacteria enter via minor epidermal breaks during sex, cause local lesions, drain to inguinal nodes; PMNs and complement/antibody participate in killing. Reinfection is common—no solid immunity. Historical: Basserau (1842) distinguished chancroid from syphilis; Rollert (1859) described mixed chancre; Ducrey (1889) identified the organism; Unna described histology; Albritton (1901) isolated it on Himmel medium.

Treatment

Drug therapy, supportive therapy

Preventive Measures

Prophylactic chemicals alone (argentum proteinicum, calomel) without condoms are ineffective. Avoid promiscuity; treat promiscuous contacts; no sex until cured. Early diagnosis/treatment/cure reduces reservoirs; asymptomatic carriers warrant prophylactic treatment. Education and prohibition of prostitution cut transmission.

Department to Visit

It is recommended to visit the STD department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.