Chancroid (Ulcus Molle, Soft Chancre)

Introduction

An infectious disease caused by Haemophilus ducreyi, a small gram-negative bacillus
Common in the tropics, especially in Africa, the Far East, and the Caribbean
Persons may present with chancroid outside endemic regions; sporadic outbreaks of infection occur in Europe and North America

Clinical features

Incubation period is about 3 - 7 days
Begins as a small, tender papule, changing into a pustule which rapidly progresses to a painful ulcer with a bright red areola
Neither the edge nor base of the ulcer is indurated (unlike syphilis)
- The ulcer feels soft, hence the name 'soft sore' (ulcus molle)
With superimposed bacterial infection it often feels indurated
The ulcers may be multiple due to auto-inoculation
Sites of predilection in men are the prepuce, frenulum, glans or shaft of the penis
In women the labia, fourchette, vestibule, clitoris, cervix, or perineum are favored sites
Lesions may cause dyspareunia, pain on voiding or defaecation and vaginal discharge
Women may be asymptomatic carriers
About 7 - 14 days after the appearance of the ulcer, a bubo appears
- A mass of gland smatted together, of tenad herent to the overlying skin
The glands above the inguinal ligament are usually affected, and often there is a unilateral enlargement
Central softening is often found and if untreated the bubo may rupture and discharge through a fistula
The combination of a painful genital ulcer and suppurative inguinal adenopathy is almost pathognomonic of chancroid
Patient may present with bubo, the initial ulcer having healed
Atypical lesions have been reported in HIV-infected individuals
- More extensive, or multiple lesions sometimes accompanied by systemic manifestations such as fever and chills

Complications

Progressive ulceration and amputation of the phallus, particularly in HIV patients

Differential diagnoses

Other causes of genital ulcers:

Investigations

Microscopy, culture and sensitivity of discharge from ulcer
Serological tests e.g. complement fixation (CF); microimmuno-fluorescence (MIF) test; PCR

Treatment goals

Drug treatment

Recommended regimen:

Ciprofloxacin 500 mg orally every 12 hours for 3 days

Or:

Erythromycin 500 mg orally every 6 hours for 7 days

Or:

Azithromycin 1 g orally as a single dose

Alternative regimen:

Ceftriaxone, 250 mg by intramuscular injection, as a single dose

Adjuvant therapy

Keep ulcerative lesions clean
Aspirate fluctuant lymph nodes through the surrounding healthy skin, preferably from a superior approach to prevent persistent dripping and sinus formation
Incision and drainage, or excision of nodes may delay healing and is not recommended

Follow-up

All patients should be followed up until there is clear evidence of improvement or cure
In patients infected with HIV, treatment may appear to be less effective, but this may be a result of co-infection with genital herpes or syphilis
Chancroid and HIV infection are closely associated and therapeutic failure is likely to be seen with increasing frequency
Patients should therefore be followed up weekly until there is clear evidence of improvement

Notable adverse drug reactions, contraindications and caution

Prevention

Nigeria